| Message ID | 20241017091734.2286-1-a@unstable.cc |
|---|---|
| State | New |
| Headers | show |
| Series | [v3] nss: reject invalid port passed to getaddrinfo [BZ #16208] | expand |
On Okt 17 2024, Antonio Quartulli wrote: > Similarly, also when passing 0 or an out of range value, no error > is thrown while it should. This is no longer accurate as 0 is allowed again. > @@ -2375,7 +2375,19 @@ getaddrinfo (const char *name, const char *service, > return EAI_NONAME; > } > > - gaih_service.num = -1; > + /* 0 means "no numeric port provided" (which is equivalent to > + passing 0 as port) */ > + gaih_service.num = 0; > + } > + /* port number must be in range [0, USHRT_MAX]. > + Any other value is invalid. > + strtoul returns ULONG_MAX in case of out-of-range > + input and it is caught by this check */ > + else if (gaih_service.num > USHRT_MAX) > + { > + /* provided numeric string is invalid */ Please write the comments as proper sentences.
* Antonio Quartulli: > + err |= do_one_test ("0", 0); // should succeed > + err |= do_one_test ("70000", EAI_NONAME); > + err |= do_one_test ("-1", EAI_NONAME); > + err |= do_one_test ("18446744073709551616", EAI_NONAME); > + err |= do_one_test ("-18446744073709551616", EAI_NONAME); If you revise this, please add additional tests with INT_MIN/INT_MAX/UINT_MAX/ULONG_MAX. The critical constants differ on 32-bit architectures. Not that I expect any bugs here, just for completeness.
Hi, On 17/10/2024 11:46, Andreas Schwab wrote: > On Okt 17 2024, Antonio Quartulli wrote: > >> Similarly, also when passing 0 or an out of range value, no error >> is thrown while it should. > > This is no longer accurate as 0 is allowed again. Ouch, you're right. Will revise that in v4. > >> @@ -2375,7 +2375,19 @@ getaddrinfo (const char *name, const char *service, >> return EAI_NONAME; >> } >> >> - gaih_service.num = -1; >> + /* 0 means "no numeric port provided" (which is equivalent to >> + passing 0 as port) */ >> + gaih_service.num = 0; >> + } >> + /* port number must be in range [0, USHRT_MAX]. >> + Any other value is invalid. >> + strtoul returns ULONG_MAX in case of out-of-range >> + input and it is caught by this check */ >> + else if (gaih_service.num > USHRT_MAX) >> + { >> + /* provided numeric string is invalid */ > > Please write the comments as proper sentences. ACK Regards, >
On 17/10/2024 12:01, Florian Weimer wrote: > * Antonio Quartulli: > >> + err |= do_one_test ("0", 0); // should succeed >> + err |= do_one_test ("70000", EAI_NONAME); >> + err |= do_one_test ("-1", EAI_NONAME); >> + err |= do_one_test ("18446744073709551616", EAI_NONAME); >> + err |= do_one_test ("-18446744073709551616", EAI_NONAME); > > If you revise this, please add additional tests with > INT_MIN/INT_MAX/UINT_MAX/ULONG_MAX. The critical constants differ on > 32-bit architectures. Not that I expect any bugs here, just for > completeness. Sure thing! Regards,
diff --git a/nss/Makefile b/nss/Makefile index 9331b3308c..94acfd0e38 100644 --- a/nss/Makefile +++ b/nss/Makefile @@ -321,6 +321,7 @@ tests := \ tst-getaddrinfo \ tst-getaddrinfo2 \ tst-getaddrinfo3 \ + tst-getaddrinfo6 \ tst-gethnm \ tst-getpw \ tst-gshadow \ diff --git a/nss/getaddrinfo.c b/nss/getaddrinfo.c index 3ccd3905fa..32c2672aaa 100644 --- a/nss/getaddrinfo.c +++ b/nss/getaddrinfo.c @@ -95,7 +95,7 @@ SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. struct gaih_service { const char *name; - int num; + unsigned long num; }; struct gaih_servtuple @@ -2375,7 +2375,19 @@ getaddrinfo (const char *name, const char *service, return EAI_NONAME; } - gaih_service.num = -1; + /* 0 means "no numeric port provided" (which is equivalent to + passing 0 as port) */ + gaih_service.num = 0; + } + /* port number must be in range [0, USHRT_MAX]. + Any other value is invalid. + strtoul returns ULONG_MAX in case of out-of-range + input and it is caught by this check */ + else if (gaih_service.num > USHRT_MAX) + { + /* provided numeric string is invalid */ + __free_in6ai (in6ai); + return EAI_NONAME; } pservice = &gaih_service; diff --git a/nss/tst-getaddrinfo6.c b/nss/tst-getaddrinfo6.c new file mode 100644 index 0000000000..c237315fd0 --- /dev/null +++ b/nss/tst-getaddrinfo6.c @@ -0,0 +1,67 @@ +/* Test invalid port/service lookup [BZ #16208]. + Copyright (C) 2014-2024 Free Software Foundation, Inc. + This file is part of the GNU C Library. + + The GNU C Library is free software; you can redistribute it and/or + modify it under the terms of the GNU Lesser General Public + License as published by the Free Software Foundation; either + version 2.1 of the License, or (at your option) any later version. + + The GNU C Library is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU + Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public + License along with the GNU C Library; if not, see + <https://www.gnu.org/licenses/>. */ + +#include <stdio.h> +#include <string.h> +#include <sys/types.h> +#include <sys/socket.h> +#include <netinet/in.h> +#include <netdb.h> + +static int +do_one_test (const char *service, int expected_err) +{ + const int family[2] = { AF_INET, AF_INET6 }; + struct addrinfo hints, *aitop; + int index, gaierr; + int result = 0; + + for (index = 0; index < sizeof (family) / sizeof (family[0]); ++index) + { + memset (&hints, '\0', sizeof (hints)); + hints.ai_family = family[index]; + + gaierr = getaddrinfo (NULL, service, &hints, &aitop); + if (gaierr != expected_err) + { + printf ("FAIL getaddrinfo returned %d, should return %d\n", + gaierr, expected_err); + result = 1; + } + } + + return result; +} + + +static int +do_test (void) +{ + int err = 0; + + err |= do_one_test ("0", 0); // should succeed + err |= do_one_test ("70000", EAI_NONAME); + err |= do_one_test ("-1", EAI_NONAME); + err |= do_one_test ("18446744073709551616", EAI_NONAME); + err |= do_one_test ("-18446744073709551616", EAI_NONAME); + + return err; +} +#define TEST_FUNCTION do_test () + +#include "../test-skeleton.c"
When passing a numeric string as port/service to getaddrinfo() representing a number larger than 65535, the function will not complain and will simply extract the lowest 16bits of the converted number. Specifically, the string is converted to int by calling strtoul() and later it is moved to gaih_servtuple.num after passing through htons(). For example, invoking getaddrinfo() with service equal to "70000" will result in no error and ai_addr->sin_port set to 4464. This issue was (re)discovered by researcher Anqi Chen while stress testing OpenVPN with invalid config parameters. Thanks a lot to Arne Schwabe for finding out that the root cause was hidden inside glibc. Similarly, also when passing 0 or an out of range value, no error is thrown while it should. Add proper checks to reject invalid values immediately. The 'num' member has been converted to unsigned long in order to properly store the result of strtoul(). Then, while checking for 'num' being greater than USHRT_MAX, we also catch overflows/out-of-range values (strtoul() returns ULONG_MAX in that case). Cc: Arne Schwabe <arne@rfc2549.org> Cc: Cristina Nita-Rotaru <crisn@ccs.neu.edu> Reported-by: Anqi Chen <chen.anqi3@northeastern.edu> Signed-off-by: Antonio Quartulli <a@unstable.cc> --- Changes from v2: * allowed specifying 0 as port number (equivalent to not passing any port) * changed unit-test to check success when passing 0 as port --- nss/Makefile | 1 + nss/getaddrinfo.c | 16 ++++++++-- nss/tst-getaddrinfo6.c | 67 ++++++++++++++++++++++++++++++++++++++++++ 3 files changed, 82 insertions(+), 2 deletions(-) create mode 100644 nss/tst-getaddrinfo6.c