Message ID | 20231018130847.1570121-1-josimmon@redhat.com |
---|---|
State | New |
Headers | show |
Series | [v2] elf: dl-load: Get rid of alloca usage. | expand |
On 18/10/23 10:08, Joe Simmons-Talbott wrote: > Replace alloca usage with scratch_buffers. Change the semantics of > is_trusted_path_normalize to return 1, 0, or -1 on error. Change > _dl_dst_substitute to return NULL on error and update callers to handle > the NULL return value. > --- > Changes to v1: > * _dl_dst_substitute returns NULL on failure. > * update callers of _dl_dst_substitute to handle NULL return value. > * Add missing scratch_buffer_free calls. > > elf/dl-deps.c | 5 +-- > elf/dl-load.c | 89 ++++++++++++++++++++++++++++++++++++++++++--------- > 2 files changed, 77 insertions(+), 17 deletions(-) > > diff --git a/elf/dl-deps.c b/elf/dl-deps.c > index 0549b4a4ff..c6f67c3e27 100644 > --- a/elf/dl-deps.c > +++ b/elf/dl-deps.c > @@ -100,8 +100,9 @@ DST not allowed in SUID/SGID programs")); \ > __dst_cnt)); \ > \ > __result = _dl_dst_substitute (l, __str, __newp); \ > - \ > - if (*__result == '\0') \ > + if (__result == NULL) \ > + _dl_signal_error (0, __str, NULL, N_("Memory allocation failed")); \ We already have the 'Memory allocation failure' message, so it won't need to add another translation. > + else if (*__result == '\0') \ > { \ > /* The replacement for the DST is not known. We can't \ > processed. */ \ > diff --git a/elf/dl-load.c b/elf/dl-load.c > index 2923b1141d..23b3b80c88 100644 > --- a/elf/dl-load.c > +++ b/elf/dl-load.c > @@ -21,6 +21,7 @@ > #include <errno.h> > #include <fcntl.h> > #include <libintl.h> > +#include <scratch_buffer.h> > #include <stdbool.h> > #include <stdlib.h> > #include <string.h> > @@ -124,14 +125,21 @@ static const size_t system_dirs_len[] = > }; > #define nsystem_dirs_len array_length (system_dirs_len) > > -static bool > +static int > is_trusted_path_normalize (const char *path, size_t len) > { > if (len == 0) > - return false; > + return 0; > > - char *npath = (char *) alloca (len + 2); > + struct scratch_buffer sbuf; > + scratch_buffer_init (&sbuf); > + > + if (!scratch_buffer_set_array_size (&sbuf, 1, len + 2)) > + return -1; > + > + char *npath = sbuf.data; > char *wnp = npath; > + > while (*path != '\0') > { > if (path[0] == '/') > @@ -171,13 +179,17 @@ is_trusted_path_normalize (const char *path, size_t len) > { > if (wnp - npath >= system_dirs_len[idx] > && memcmp (trun, npath, system_dirs_len[idx]) == 0) > - /* Found it. */ > - return true; > + { > + scratch_buffer_free (&sbuf); > + /* Found it. */ > + return 1; > + } > > trun += system_dirs_len[idx] + 1; > } > > - return false; > + scratch_buffer_free (&sbuf); > + return 0; > } I think you can simplify this by using a temporary variable: int r = 0; for (size_t idx = 0; idx < nsystem_dirs_len; ++idx) { if (wnp - npath >= system_dirs_len[idx] && memcmp (trun, npath, system_dirs_len[idx]) == 0) /* Found it. */ { r = 1; break; } trun += system_dirs_len[idx] + 1; } scratch_buffer_free (&sbuf); > > /* Given a substring starting at INPUT, just after the DST '$' start > @@ -270,7 +282,7 @@ _dl_dst_count (const char *input) > least equal to the value returned by DL_DST_REQUIRED. Note that it > is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to > have colons, but we treat those as literal colons here, not as path > - list delimiters. */ > + list delimiters. Returns NULL on failure. */ > char * > _dl_dst_substitute (struct link_map *l, const char *input, char *result) > { > @@ -283,6 +295,7 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) > char *wp = result; > const char *start = input; > bool check_for_trusted = false; > + int itpn; > > do > { > @@ -362,8 +375,14 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) > trusted to have designed this correctly. Only $ORIGIN is tested in > this way because it may be manipulated in some ways with hard > links. */ > - if (__glibc_unlikely (check_for_trusted) > - && !is_trusted_path_normalize (result, wp - result)) > + itpn = is_trusted_path_normalize (result, wp - result); > + if (itpn == -1) > + { > + _dl_signal_error (ENOMEM, NULL, NULL, N_("Failed to allocate memory")); > + return NULL; > + } > + > + if (__glibc_unlikely (check_for_trusted) && itpn) > { > *result = '\0'; > return result; This is wrong, it just want to call is_trusted_path_normalize if check_for_trusted is set. I think it should be: if (__glibc_unlikely (check_for_trusted)) { int r = is_trusted_path_normalize (result, wp - result); if (r == -1) return NULL; else if (r == 0) { *result = '\0'; return result; } } So we report back any allocation failure, and clear the result if the canonical path is not related to system dirs. > @@ -951,6 +970,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > /* Initialize to keep the compiler happy. */ > const char *errstring = NULL; > int errval = 0; > + struct scratch_buffer sbuf; > + scratch_buffer_init (&sbuf); > > /* Get file information. To match the kernel behavior, do not fill > in this information for the executable in case of an explicit > @@ -982,6 +1003,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > free ((void *) l->l_phdr); > free (l); > free (realname); > + scratch_buffer_free (&sbuf); > _dl_signal_error (errval, name, NULL, errstring); > } > > @@ -998,6 +1020,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > free (realname); > add_name_to_object (l, name); > > + scratch_buffer_free (&sbuf); > return l; > } > } > @@ -1029,6 +1052,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > /* Add the map for the mirrored object to the object list. */ > _dl_add_to_namespace_list (l, nsid); > > + scratch_buffer_free (&sbuf); > return l; > } > #endif > @@ -1039,6 +1063,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > loaded. So return now. */ > free (realname); > __close_nocancel (fd); > + scratch_buffer_free (&sbuf); > return NULL; > } > > @@ -1071,7 +1096,12 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > phdr = (void *) (fbp->buf + header->e_phoff); > else > { > - phdr = alloca (maplength); > + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) > + { > + errstring = N_("cannot allocate memory"); > + goto lose_errno; > + } > + phdr = sbuf.data; > if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, > header->e_phoff) != maplength) > { Please move this alloca removal to another patch. > @@ -1485,7 +1515,10 @@ cannot enable executable stack as shared object requires"); > > /* Skip auditing and debugger notification when called from 'sprof'. */ > if (mode & __RTLD_SPROF) > - return l; > + { > + scratch_buffer_free (&sbuf); > + return l; > + } > > /* Signal that we are going to add new objects. */ > struct r_debug *r = _dl_debug_update (nsid); > @@ -1515,6 +1548,7 @@ cannot enable executable stack as shared object requires"); > _dl_audit_objopen (l, nsid); > #endif > > + scratch_buffer_free (&sbuf); > return l; > } > > @@ -1598,6 +1632,8 @@ open_verify (const char *name, int fd, > /* Initialize it to make the compiler happy. */ > const char *errstring = NULL; > int errval = 0; > + struct scratch_buffer sbuf; > + scratch_buffer_init (&sbuf); > > #ifdef SHARED > /* Give the auditing libraries a chance. */ > @@ -1660,6 +1696,7 @@ open_verify (const char *name, int fd, > name = strdupa (realname); > free (realname); > } > + scratch_buffer_free (&sbuf); > __close_nocancel (fd); > _dl_signal_error (errval, name, NULL, errstring); > } > @@ -1696,6 +1733,7 @@ open_verify (const char *name, int fd, > 32-bit and 64-bit binaries can be run this might > happen. */ > *found_other_class = true; > + scratch_buffer_free (&sbuf); > __close_nocancel (fd); > __set_errno (ENOENT); > return -1; > @@ -1734,6 +1772,7 @@ open_verify (const char *name, int fd, > } > if (! __glibc_likely (elf_machine_matches_host (ehdr))) > { > + scratch_buffer_free (&sbuf); > __close_nocancel (fd); > __set_errno (ENOENT); > return -1; > @@ -1755,7 +1794,14 @@ open_verify (const char *name, int fd, > phdr = (void *) (fbp->buf + ehdr->e_phoff); > else > { > - phdr = alloca (maplength); > + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) > + { > + errval = errno; > + errstring = N_("cannot allocate memory"); > + goto lose; > + } > + phdr = sbuf.data; > + > if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, > ehdr->e_phoff) != maplength) > { Please move this alloca removal to another patch. > @@ -1769,6 +1815,7 @@ open_verify (const char *name, int fd, > (phdr, ehdr->e_phnum, fbp->buf, fbp->len, > loader, fd))) > { > + scratch_buffer_free (&sbuf); > __close_nocancel (fd); > __set_errno (ENOENT); > return -1; > @@ -1776,6 +1823,7 @@ open_verify (const char *name, int fd, > > } > > + scratch_buffer_free (&sbuf); > return fd; > } > > @@ -1796,13 +1844,18 @@ open_path (const char *name, size_t namelen, int mode, > int fd = -1; > const char *current_what = NULL; > int any = 0; > + struct scratch_buffer sbuf; > + scratch_buffer_init (&sbuf); > > if (__glibc_unlikely (dirs == NULL)) > /* We're called before _dl_init_paths when loading the main executable > given on the command line when rtld is run directly. */ > return -1; > > - buf = alloca (max_dirnamelen + max_capstrlen + namelen); > + if (!scratch_buffer_set_array_size (&sbuf, 1, > + max_dirnamelen + max_capstrlen + namelen)) > + return -1; > + buf = sbuf.data; > do > { > struct r_search_path_elem *this_dir = *dirs; Please move this alloca removal to another patch. > @@ -1901,6 +1954,7 @@ open_path (const char *name, size_t namelen, int mode, > if (*realname != NULL) > { > memcpy (*realname, buf, buflen); > + scratch_buffer_free (&sbuf); > return fd; > } > else > @@ -1908,12 +1962,16 @@ open_path (const char *name, size_t namelen, int mode, > /* No memory for the name, we certainly won't be able > to load and link it. */ > __close_nocancel (fd); > + scratch_buffer_free (&sbuf); > return -1; > } > } > if (here_any && (err = errno) != ENOENT && err != EACCES) > - /* The file exists and is readable, but something went wrong. */ > - return -1; > + { > + /* The file exists and is readable, but something went wrong. */ > + scratch_buffer_free (&sbuf); > + return -1; > + } > > /* Remember whether we found anything. */ > any |= here_any; > @@ -1934,6 +1992,7 @@ open_path (const char *name, size_t namelen, int mode, > sps->dirs = (void *) -1; > } > > + scratch_buffer_free (&sbuf); > return -1; > } > You are still missing the possible allocation failure on expand_dynamic_string_token, since if _dl_dst_substitute returns NULL it requires to free the result: Also, on expand_dynamic_string_token call at fillin_rpath, now that we have a possible memory allocation failure I think it would be worth to add a _dl_signal_error if the function returns NULL.
On Thu, Oct 19, 2023 at 10:33:55AM -0300, Adhemerval Zanella Netto wrote: > > > On 18/10/23 10:08, Joe Simmons-Talbott wrote: > > Replace alloca usage with scratch_buffers. Change the semantics of > > is_trusted_path_normalize to return 1, 0, or -1 on error. Change > > _dl_dst_substitute to return NULL on error and update callers to handle > > the NULL return value. > > --- > > Changes to v1: > > * _dl_dst_substitute returns NULL on failure. > > * update callers of _dl_dst_substitute to handle NULL return value. > > * Add missing scratch_buffer_free calls. > > > > elf/dl-deps.c | 5 +-- > > elf/dl-load.c | 89 ++++++++++++++++++++++++++++++++++++++++++--------- > > 2 files changed, 77 insertions(+), 17 deletions(-) > > > > diff --git a/elf/dl-deps.c b/elf/dl-deps.c > > index 0549b4a4ff..c6f67c3e27 100644 > > --- a/elf/dl-deps.c > > +++ b/elf/dl-deps.c > > @@ -100,8 +100,9 @@ DST not allowed in SUID/SGID programs")); \ > > __dst_cnt)); \ > > \ > > __result = _dl_dst_substitute (l, __str, __newp); \ > > - \ > > - if (*__result == '\0') \ > > + if (__result == NULL) \ > > + _dl_signal_error (0, __str, NULL, N_("Memory allocation failed")); \ > > We already have the 'Memory allocation failure' message, so it won't need to > add another translation. > I've posted a v3 patch that makes all of the changes you've suggested. Thanks for the review. Thanks, Joe > > + else if (*__result == '\0') \ > > { \ > > /* The replacement for the DST is not known. We can't \ > > processed. */ \ > > diff --git a/elf/dl-load.c b/elf/dl-load.c > > index 2923b1141d..23b3b80c88 100644 > > --- a/elf/dl-load.c > > +++ b/elf/dl-load.c > > @@ -21,6 +21,7 @@ > > #include <errno.h> > > #include <fcntl.h> > > #include <libintl.h> > > +#include <scratch_buffer.h> > > #include <stdbool.h> > > #include <stdlib.h> > > #include <string.h> > > @@ -124,14 +125,21 @@ static const size_t system_dirs_len[] = > > }; > > #define nsystem_dirs_len array_length (system_dirs_len) > > > > -static bool > > +static int > > is_trusted_path_normalize (const char *path, size_t len) > > { > > if (len == 0) > > - return false; > > + return 0; > > > > - char *npath = (char *) alloca (len + 2); > > + struct scratch_buffer sbuf; > > + scratch_buffer_init (&sbuf); > > + > > + if (!scratch_buffer_set_array_size (&sbuf, 1, len + 2)) > > + return -1; > > + > > + char *npath = sbuf.data; > > char *wnp = npath; > > + > > while (*path != '\0') > > { > > if (path[0] == '/') > > @@ -171,13 +179,17 @@ is_trusted_path_normalize (const char *path, size_t len) > > { > > if (wnp - npath >= system_dirs_len[idx] > > && memcmp (trun, npath, system_dirs_len[idx]) == 0) > > - /* Found it. */ > > - return true; > > + { > > + scratch_buffer_free (&sbuf); > > + /* Found it. */ > > + return 1; > > + } > > > > trun += system_dirs_len[idx] + 1; > > } > > > > - return false; > > + scratch_buffer_free (&sbuf); > > + return 0; > > } > > I think you can simplify this by using a temporary variable: > > int r = 0; > for (size_t idx = 0; idx < nsystem_dirs_len; ++idx) > { > if (wnp - npath >= system_dirs_len[idx] > && memcmp (trun, npath, system_dirs_len[idx]) == 0) > /* Found it. */ > { > r = 1; > break; > } > > trun += system_dirs_len[idx] + 1; > } > scratch_buffer_free (&sbuf); > > > > > > /* Given a substring starting at INPUT, just after the DST '$' start > > @@ -270,7 +282,7 @@ _dl_dst_count (const char *input) > > least equal to the value returned by DL_DST_REQUIRED. Note that it > > is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to > > have colons, but we treat those as literal colons here, not as path > > - list delimiters. */ > > + list delimiters. Returns NULL on failure. */ > > char * > > _dl_dst_substitute (struct link_map *l, const char *input, char *result) > > { > > @@ -283,6 +295,7 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) > > char *wp = result; > > const char *start = input; > > bool check_for_trusted = false; > > + int itpn; > > > > do > > { > > @@ -362,8 +375,14 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) > > trusted to have designed this correctly. Only $ORIGIN is tested in > > this way because it may be manipulated in some ways with hard > > links. */ > > - if (__glibc_unlikely (check_for_trusted) > > - && !is_trusted_path_normalize (result, wp - result)) > > + itpn = is_trusted_path_normalize (result, wp - result); > > + if (itpn == -1) > > + { > > + _dl_signal_error (ENOMEM, NULL, NULL, N_("Failed to allocate memory")); > > + return NULL; > > + } > > + > > + if (__glibc_unlikely (check_for_trusted) && itpn) > > { > > *result = '\0'; > > return result; > > This is wrong, it just want to call is_trusted_path_normalize if check_for_trusted is > set. I think it should be: > > if (__glibc_unlikely (check_for_trusted)) > { > int r = is_trusted_path_normalize (result, wp - result); > if (r == -1) > return NULL; > else if (r == 0) > { > *result = '\0'; > return result; > } > } > > So we report back any allocation failure, and clear the result if the canonical path > is not related to system dirs. > > > @@ -951,6 +970,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > /* Initialize to keep the compiler happy. */ > > const char *errstring = NULL; > > int errval = 0; > > + struct scratch_buffer sbuf; > > + scratch_buffer_init (&sbuf); > > > > /* Get file information. To match the kernel behavior, do not fill > > in this information for the executable in case of an explicit > > @@ -982,6 +1003,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > free ((void *) l->l_phdr); > > free (l); > > free (realname); > > + scratch_buffer_free (&sbuf); > > _dl_signal_error (errval, name, NULL, errstring); > > } > > > > @@ -998,6 +1020,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > free (realname); > > add_name_to_object (l, name); > > > > + scratch_buffer_free (&sbuf); > > return l; > > } > > } > > @@ -1029,6 +1052,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > /* Add the map for the mirrored object to the object list. */ > > _dl_add_to_namespace_list (l, nsid); > > > > + scratch_buffer_free (&sbuf); > > return l; > > } > > #endif > > @@ -1039,6 +1063,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > loaded. So return now. */ > > free (realname); > > __close_nocancel (fd); > > + scratch_buffer_free (&sbuf); > > return NULL; > > } > > > > @@ -1071,7 +1096,12 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, > > phdr = (void *) (fbp->buf + header->e_phoff); > > else > > { > > - phdr = alloca (maplength); > > + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) > > + { > > + errstring = N_("cannot allocate memory"); > > + goto lose_errno; > > + } > > + phdr = sbuf.data; > > if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, > > header->e_phoff) != maplength) > > { > > Please move this alloca removal to another patch. > > > @@ -1485,7 +1515,10 @@ cannot enable executable stack as shared object requires"); > > > > /* Skip auditing and debugger notification when called from 'sprof'. */ > > if (mode & __RTLD_SPROF) > > - return l; > > + { > > + scratch_buffer_free (&sbuf); > > + return l; > > + } > > > > /* Signal that we are going to add new objects. */ > > struct r_debug *r = _dl_debug_update (nsid); > > @@ -1515,6 +1548,7 @@ cannot enable executable stack as shared object requires"); > > _dl_audit_objopen (l, nsid); > > #endif > > > > + scratch_buffer_free (&sbuf); > > return l; > > } > > > > @@ -1598,6 +1632,8 @@ open_verify (const char *name, int fd, > > /* Initialize it to make the compiler happy. */ > > const char *errstring = NULL; > > int errval = 0; > > + struct scratch_buffer sbuf; > > + scratch_buffer_init (&sbuf); > > > > #ifdef SHARED > > /* Give the auditing libraries a chance. */ > > @@ -1660,6 +1696,7 @@ open_verify (const char *name, int fd, > > name = strdupa (realname); > > free (realname); > > } > > + scratch_buffer_free (&sbuf); > > __close_nocancel (fd); > > _dl_signal_error (errval, name, NULL, errstring); > > } > > @@ -1696,6 +1733,7 @@ open_verify (const char *name, int fd, > > 32-bit and 64-bit binaries can be run this might > > happen. */ > > *found_other_class = true; > > + scratch_buffer_free (&sbuf); > > __close_nocancel (fd); > > __set_errno (ENOENT); > > return -1; > > @@ -1734,6 +1772,7 @@ open_verify (const char *name, int fd, > > } > > if (! __glibc_likely (elf_machine_matches_host (ehdr))) > > { > > + scratch_buffer_free (&sbuf); > > __close_nocancel (fd); > > __set_errno (ENOENT); > > return -1; > > @@ -1755,7 +1794,14 @@ open_verify (const char *name, int fd, > > phdr = (void *) (fbp->buf + ehdr->e_phoff); > > else > > { > > - phdr = alloca (maplength); > > + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) > > + { > > + errval = errno; > > + errstring = N_("cannot allocate memory"); > > + goto lose; > > + } > > + phdr = sbuf.data; > > + > > if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, > > ehdr->e_phoff) != maplength) > > { > > Please move this alloca removal to another patch. > > > @@ -1769,6 +1815,7 @@ open_verify (const char *name, int fd, > > (phdr, ehdr->e_phnum, fbp->buf, fbp->len, > > loader, fd))) > > { > > + scratch_buffer_free (&sbuf); > > __close_nocancel (fd); > > __set_errno (ENOENT); > > return -1; > > @@ -1776,6 +1823,7 @@ open_verify (const char *name, int fd, > > > > } > > > > + scratch_buffer_free (&sbuf); > > return fd; > > } > > > > @@ -1796,13 +1844,18 @@ open_path (const char *name, size_t namelen, int mode, > > int fd = -1; > > const char *current_what = NULL; > > int any = 0; > > + struct scratch_buffer sbuf; > > + scratch_buffer_init (&sbuf); > > > > if (__glibc_unlikely (dirs == NULL)) > > /* We're called before _dl_init_paths when loading the main executable > > given on the command line when rtld is run directly. */ > > return -1; > > > > - buf = alloca (max_dirnamelen + max_capstrlen + namelen); > > + if (!scratch_buffer_set_array_size (&sbuf, 1, > > + max_dirnamelen + max_capstrlen + namelen)) > > + return -1; > > + buf = sbuf.data; > > do > > { > > struct r_search_path_elem *this_dir = *dirs; > > Please move this alloca removal to another patch. > > > @@ -1901,6 +1954,7 @@ open_path (const char *name, size_t namelen, int mode, > > if (*realname != NULL) > > { > > memcpy (*realname, buf, buflen); > > + scratch_buffer_free (&sbuf); > > return fd; > > } > > else > > @@ -1908,12 +1962,16 @@ open_path (const char *name, size_t namelen, int mode, > > /* No memory for the name, we certainly won't be able > > to load and link it. */ > > __close_nocancel (fd); > > + scratch_buffer_free (&sbuf); > > return -1; > > } > > } > > if (here_any && (err = errno) != ENOENT && err != EACCES) > > - /* The file exists and is readable, but something went wrong. */ > > - return -1; > > + { > > + /* The file exists and is readable, but something went wrong. */ > > + scratch_buffer_free (&sbuf); > > + return -1; > > + } > > > > /* Remember whether we found anything. */ > > any |= here_any; > > @@ -1934,6 +1992,7 @@ open_path (const char *name, size_t namelen, int mode, > > sps->dirs = (void *) -1; > > } > > > > + scratch_buffer_free (&sbuf); > > return -1; > > } > > > > You are still missing the possible allocation failure on expand_dynamic_string_token, > since if _dl_dst_substitute returns NULL it requires to free the result: > > Also, on expand_dynamic_string_token call at fillin_rpath, now that we have a possible > memory allocation failure I think it would be worth to add a _dl_signal_error if the > function returns NULL. >
diff --git a/elf/dl-deps.c b/elf/dl-deps.c index 0549b4a4ff..c6f67c3e27 100644 --- a/elf/dl-deps.c +++ b/elf/dl-deps.c @@ -100,8 +100,9 @@ DST not allowed in SUID/SGID programs")); \ __dst_cnt)); \ \ __result = _dl_dst_substitute (l, __str, __newp); \ - \ - if (*__result == '\0') \ + if (__result == NULL) \ + _dl_signal_error (0, __str, NULL, N_("Memory allocation failed")); \ + else if (*__result == '\0') \ { \ /* The replacement for the DST is not known. We can't \ processed. */ \ diff --git a/elf/dl-load.c b/elf/dl-load.c index 2923b1141d..23b3b80c88 100644 --- a/elf/dl-load.c +++ b/elf/dl-load.c @@ -21,6 +21,7 @@ #include <errno.h> #include <fcntl.h> #include <libintl.h> +#include <scratch_buffer.h> #include <stdbool.h> #include <stdlib.h> #include <string.h> @@ -124,14 +125,21 @@ static const size_t system_dirs_len[] = }; #define nsystem_dirs_len array_length (system_dirs_len) -static bool +static int is_trusted_path_normalize (const char *path, size_t len) { if (len == 0) - return false; + return 0; - char *npath = (char *) alloca (len + 2); + struct scratch_buffer sbuf; + scratch_buffer_init (&sbuf); + + if (!scratch_buffer_set_array_size (&sbuf, 1, len + 2)) + return -1; + + char *npath = sbuf.data; char *wnp = npath; + while (*path != '\0') { if (path[0] == '/') @@ -171,13 +179,17 @@ is_trusted_path_normalize (const char *path, size_t len) { if (wnp - npath >= system_dirs_len[idx] && memcmp (trun, npath, system_dirs_len[idx]) == 0) - /* Found it. */ - return true; + { + scratch_buffer_free (&sbuf); + /* Found it. */ + return 1; + } trun += system_dirs_len[idx] + 1; } - return false; + scratch_buffer_free (&sbuf); + return 0; } /* Given a substring starting at INPUT, just after the DST '$' start @@ -270,7 +282,7 @@ _dl_dst_count (const char *input) least equal to the value returned by DL_DST_REQUIRED. Note that it is possible for a DT_NEEDED, DT_AUXILIARY, and DT_FILTER entries to have colons, but we treat those as literal colons here, not as path - list delimiters. */ + list delimiters. Returns NULL on failure. */ char * _dl_dst_substitute (struct link_map *l, const char *input, char *result) { @@ -283,6 +295,7 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) char *wp = result; const char *start = input; bool check_for_trusted = false; + int itpn; do { @@ -362,8 +375,14 @@ _dl_dst_substitute (struct link_map *l, const char *input, char *result) trusted to have designed this correctly. Only $ORIGIN is tested in this way because it may be manipulated in some ways with hard links. */ - if (__glibc_unlikely (check_for_trusted) - && !is_trusted_path_normalize (result, wp - result)) + itpn = is_trusted_path_normalize (result, wp - result); + if (itpn == -1) + { + _dl_signal_error (ENOMEM, NULL, NULL, N_("Failed to allocate memory")); + return NULL; + } + + if (__glibc_unlikely (check_for_trusted) && itpn) { *result = '\0'; return result; @@ -951,6 +970,8 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, /* Initialize to keep the compiler happy. */ const char *errstring = NULL; int errval = 0; + struct scratch_buffer sbuf; + scratch_buffer_init (&sbuf); /* Get file information. To match the kernel behavior, do not fill in this information for the executable in case of an explicit @@ -982,6 +1003,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, free ((void *) l->l_phdr); free (l); free (realname); + scratch_buffer_free (&sbuf); _dl_signal_error (errval, name, NULL, errstring); } @@ -998,6 +1020,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, free (realname); add_name_to_object (l, name); + scratch_buffer_free (&sbuf); return l; } } @@ -1029,6 +1052,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, /* Add the map for the mirrored object to the object list. */ _dl_add_to_namespace_list (l, nsid); + scratch_buffer_free (&sbuf); return l; } #endif @@ -1039,6 +1063,7 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, loaded. So return now. */ free (realname); __close_nocancel (fd); + scratch_buffer_free (&sbuf); return NULL; } @@ -1071,7 +1096,12 @@ _dl_map_object_from_fd (const char *name, const char *origname, int fd, phdr = (void *) (fbp->buf + header->e_phoff); else { - phdr = alloca (maplength); + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) + { + errstring = N_("cannot allocate memory"); + goto lose_errno; + } + phdr = sbuf.data; if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, header->e_phoff) != maplength) { @@ -1485,7 +1515,10 @@ cannot enable executable stack as shared object requires"); /* Skip auditing and debugger notification when called from 'sprof'. */ if (mode & __RTLD_SPROF) - return l; + { + scratch_buffer_free (&sbuf); + return l; + } /* Signal that we are going to add new objects. */ struct r_debug *r = _dl_debug_update (nsid); @@ -1515,6 +1548,7 @@ cannot enable executable stack as shared object requires"); _dl_audit_objopen (l, nsid); #endif + scratch_buffer_free (&sbuf); return l; } @@ -1598,6 +1632,8 @@ open_verify (const char *name, int fd, /* Initialize it to make the compiler happy. */ const char *errstring = NULL; int errval = 0; + struct scratch_buffer sbuf; + scratch_buffer_init (&sbuf); #ifdef SHARED /* Give the auditing libraries a chance. */ @@ -1660,6 +1696,7 @@ open_verify (const char *name, int fd, name = strdupa (realname); free (realname); } + scratch_buffer_free (&sbuf); __close_nocancel (fd); _dl_signal_error (errval, name, NULL, errstring); } @@ -1696,6 +1733,7 @@ open_verify (const char *name, int fd, 32-bit and 64-bit binaries can be run this might happen. */ *found_other_class = true; + scratch_buffer_free (&sbuf); __close_nocancel (fd); __set_errno (ENOENT); return -1; @@ -1734,6 +1772,7 @@ open_verify (const char *name, int fd, } if (! __glibc_likely (elf_machine_matches_host (ehdr))) { + scratch_buffer_free (&sbuf); __close_nocancel (fd); __set_errno (ENOENT); return -1; @@ -1755,7 +1794,14 @@ open_verify (const char *name, int fd, phdr = (void *) (fbp->buf + ehdr->e_phoff); else { - phdr = alloca (maplength); + if (!scratch_buffer_set_array_size (&sbuf, 1, maplength)) + { + errval = errno; + errstring = N_("cannot allocate memory"); + goto lose; + } + phdr = sbuf.data; + if ((size_t) __pread64_nocancel (fd, (void *) phdr, maplength, ehdr->e_phoff) != maplength) { @@ -1769,6 +1815,7 @@ open_verify (const char *name, int fd, (phdr, ehdr->e_phnum, fbp->buf, fbp->len, loader, fd))) { + scratch_buffer_free (&sbuf); __close_nocancel (fd); __set_errno (ENOENT); return -1; @@ -1776,6 +1823,7 @@ open_verify (const char *name, int fd, } + scratch_buffer_free (&sbuf); return fd; } @@ -1796,13 +1844,18 @@ open_path (const char *name, size_t namelen, int mode, int fd = -1; const char *current_what = NULL; int any = 0; + struct scratch_buffer sbuf; + scratch_buffer_init (&sbuf); if (__glibc_unlikely (dirs == NULL)) /* We're called before _dl_init_paths when loading the main executable given on the command line when rtld is run directly. */ return -1; - buf = alloca (max_dirnamelen + max_capstrlen + namelen); + if (!scratch_buffer_set_array_size (&sbuf, 1, + max_dirnamelen + max_capstrlen + namelen)) + return -1; + buf = sbuf.data; do { struct r_search_path_elem *this_dir = *dirs; @@ -1901,6 +1954,7 @@ open_path (const char *name, size_t namelen, int mode, if (*realname != NULL) { memcpy (*realname, buf, buflen); + scratch_buffer_free (&sbuf); return fd; } else @@ -1908,12 +1962,16 @@ open_path (const char *name, size_t namelen, int mode, /* No memory for the name, we certainly won't be able to load and link it. */ __close_nocancel (fd); + scratch_buffer_free (&sbuf); return -1; } } if (here_any && (err = errno) != ENOENT && err != EACCES) - /* The file exists and is readable, but something went wrong. */ - return -1; + { + /* The file exists and is readable, but something went wrong. */ + scratch_buffer_free (&sbuf); + return -1; + } /* Remember whether we found anything. */ any |= here_any; @@ -1934,6 +1992,7 @@ open_path (const char *name, size_t namelen, int mode, sps->dirs = (void *) -1; } + scratch_buffer_free (&sbuf); return -1; }