| Message ID | 20230809120344.1095219-1-bmahi496@linux.ibm.com |
|---|---|
| State | New |
| Headers | show |
| Series | string: Fix tester build with fortify enable with gcc < 12 | expand |
On 8/9/23 7:03 AM, bmahi496@linux.ibm.com wrote: > From: Mahesh Bodapati <bmahi496@linux.ibm.com> > > When building with fortify enabled, GCC < 12 issues a warning on the > fortify strncat wrapper might overflow the destination buffer. However, > GCC does not provide a specific flag to disable the warning (the > failure is tied to -Werror). So to avoid disable all errors, only > enable the check for GCC 12 or newer. > > Checked on ppc64 and x86_64. > --- > string/tester.c | 7 +++++++ > 1 file changed, 7 insertions(+) > > diff --git a/string/tester.c b/string/tester.c > index f7d4bac5a8..cf3f5ae495 100644 > --- a/string/tester.c > +++ b/string/tester.c > @@ -421,6 +421,12 @@ test_strncat (void) > (void) strncat (one, "ij", (size_t)-1); /* set sign bit in count */ > equal (one, "abcdghij", 13); > > + /* When building with fortify enabled, GCC < 12 issues a warning on the > + fortify strncat wrapper might overflow the destination buffer. However, > + GCC does not provide a specific flag to disable the warning (the > + failure is tied to -Werror). So to avoid disable all errors, only > + enable the check for GCC 12 or newer. */ > +#if __GNUC_PREREQ (12, 0) Is it possible to include a check for fortify enabled option ? > int ntest = 14; > char buf1[80] __attribute__ ((aligned (16))); > char buf2[32] __attribute__ ((aligned (16))); > @@ -464,6 +470,7 @@ test_strncat (void) > } > } > } > +#endif > } > > static void
On 09/08/23 7:10 pm, Rajalakshmi Srinivasaraghavan wrote: > > On 8/9/23 7:03 AM, bmahi496@linux.ibm.com wrote: >> From: Mahesh Bodapati <bmahi496@linux.ibm.com> >> >> When building with fortify enabled, GCC < 12 issues a warning on the >> fortify strncat wrapper might overflow the destination buffer. However, >> GCC does not provide a specific flag to disable the warning (the >> failure is tied to -Werror). So to avoid disable all errors, only >> enable the check for GCC 12 or newer. >> >> Checked on ppc64 and x86_64. >> --- >> string/tester.c | 7 +++++++ >> 1 file changed, 7 insertions(+) >> >> diff --git a/string/tester.c b/string/tester.c >> index f7d4bac5a8..cf3f5ae495 100644 >> --- a/string/tester.c >> +++ b/string/tester.c >> @@ -421,6 +421,12 @@ test_strncat (void) >> (void) strncat (one, "ij", (size_t)-1); /* set sign bit in >> count */ >> equal (one, "abcdghij", 13); >> + /* When building with fortify enabled, GCC < 12 issues a warning >> on the >> + fortify strncat wrapper might overflow the destination buffer. >> However, >> + GCC does not provide a specific flag to disable the warning (the >> + failure is tied to -Werror). So to avoid disable all errors, only >> + enable the check for GCC 12 or newer. */ >> +#if __GNUC_PREREQ (12, 0) > > Is it possible to include a check for fortify enabled option ? __USE_FORTIFY_LEVEL is 0 if fortify not enabled. I will include it in the condition and share the updated patch. > >> int ntest = 14; >> char buf1[80] __attribute__ ((aligned (16))); >> char buf2[32] __attribute__ ((aligned (16))); >> @@ -464,6 +470,7 @@ test_strncat (void) >> } >> } >> } >> +#endif >> } >> static void
On Wed, 9 Aug 2023, bmahi496--- via Libc-alpha wrote: > From: Mahesh Bodapati <bmahi496@linux.ibm.com> > > When building with fortify enabled, GCC < 12 issues a warning on the > fortify strncat wrapper might overflow the destination buffer. However, > GCC does not provide a specific flag to disable the warning (the > failure is tied to -Werror). So to avoid disable all errors, only > enable the check for GCC 12 or newer. What is the exact diagnostic message?
On 10/08/23 3:04 am, Joseph Myers wrote: > On Wed, 9 Aug 2023, bmahi496--- via Libc-alpha wrote: > >> From: Mahesh Bodapati<bmahi496@linux.ibm.com> >> >> When building with fortify enabled, GCC < 12 issues a warning on the >> fortify strncat wrapper might overflow the destination buffer. However, >> GCC does not provide a specific flag to disable the warning (the >> failure is tied to -Werror). So to avoid disable all errors, only >> enable the check for GCC 12 or newer. > What is the exact diagnostic message? The error looks like below . /In file included from ../include/bits/string_fortified.h:1,// // from ../string/string.h:548,// // from ../include/string.h:60,// // from tester.c:41,// // from inl-tester.c:6:// //In function 'strncat',// // inlined from 'test_strncat' at tester.c:446:13:// //../string/bits/string_fortified.h:138:10:*error: '__builtin_strncat' specified bound [18446744073709551600, 18446744073709551615] exceeds maximum object size 9223372036854775807 [-Werror=stringop-overread]*// // 138 | return __builtin___strncat_chk (__dest, __src, __len,// // | ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~// // 139 | __glibc_objsize (__dest));// // | ~~~~~~~~~~~~~~~~~~~~~~~~~/ >
On Thu, 10 Aug 2023, MAHESH BODAPATI wrote: > On 10/08/23 3:04 am, Joseph Myers wrote: > > On Wed, 9 Aug 2023, bmahi496--- via Libc-alpha wrote: > > > > > From: Mahesh Bodapati<bmahi496@linux.ibm.com> > > > > > > When building with fortify enabled, GCC < 12 issues a warning on the > > > fortify strncat wrapper might overflow the destination buffer. However, > > > GCC does not provide a specific flag to disable the warning (the > > > failure is tied to -Werror). So to avoid disable all errors, only > > > enable the check for GCC 12 or newer. > > What is the exact diagnostic message? > > The error looks like below . > > /In file included from ../include/bits/string_fortified.h:1,// > // from ../string/string.h:548,// > // from ../include/string.h:60,// > // from tester.c:41,// > // from inl-tester.c:6:// > //In function 'strncat',// > // inlined from 'test_strncat' at tester.c:446:13:// > //../string/bits/string_fortified.h:138:10:*error: '__builtin_strncat' > specified bound [18446744073709551600, 18446744073709551615] exceeds maximum > object size 9223372036854775807 [-Werror=stringop-overread]*// Thanks. Does it not work to disable -Wstringop-overread with the macros from libc-diag.h (moving the existing #if __GNUC_PREREQ (11, 0) DIAG_IGNORE_NEEDS_COMMENT (11, "-Wstringop-overread"); #endif to be alongside the existing -Wstringop-truncation disabling if it needs to be in effect before string.h is included)?
On 10/08/23 8:03 pm, Joseph Myers wrote: > On Thu, 10 Aug 2023, MAHESH BODAPATI wrote: > >> On 10/08/23 3:04 am, Joseph Myers wrote: >>> On Wed, 9 Aug 2023, bmahi496--- via Libc-alpha wrote: >>> >>>> From: Mahesh Bodapati<bmahi496@linux.ibm.com> >>>> >>>> When building with fortify enabled, GCC < 12 issues a warning on the >>>> fortify strncat wrapper might overflow the destination buffer. However, >>>> GCC does not provide a specific flag to disable the warning (the >>>> failure is tied to -Werror). So to avoid disable all errors, only >>>> enable the check for GCC 12 or newer. >>> What is the exact diagnostic message? >> The error looks like below . >> >> /In file included from ../include/bits/string_fortified.h:1,// >> // from ../string/string.h:548,// >> // from ../include/string.h:60,// >> // from tester.c:41,// >> // from inl-tester.c:6:// >> //In function 'strncat',// >> // inlined from 'test_strncat' at tester.c:446:13:// >> //../string/bits/string_fortified.h:138:10:*error: '__builtin_strncat' >> specified bound [18446744073709551600, 18446744073709551615] exceeds maximum >> object size 9223372036854775807 [-Werror=stringop-overread]*// > Thanks. Does it not work to disable -Wstringop-overread with the macros > from libc-diag.h (moving the existing > > #if __GNUC_PREREQ (11, 0) > DIAG_IGNORE_NEEDS_COMMENT (11, "-Wstringop-overread"); > #endif > > to be alongside the existing -Wstringop-truncation disabling if it needs > to be in effect before string.h is included)? Thanks, It's working.I will share the updated patch. >
diff --git a/string/tester.c b/string/tester.c index f7d4bac5a8..cf3f5ae495 100644 --- a/string/tester.c +++ b/string/tester.c @@ -421,6 +421,12 @@ test_strncat (void) (void) strncat (one, "ij", (size_t)-1); /* set sign bit in count */ equal (one, "abcdghij", 13); + /* When building with fortify enabled, GCC < 12 issues a warning on the + fortify strncat wrapper might overflow the destination buffer. However, + GCC does not provide a specific flag to disable the warning (the + failure is tied to -Werror). So to avoid disable all errors, only + enable the check for GCC 12 or newer. */ +#if __GNUC_PREREQ (12, 0) int ntest = 14; char buf1[80] __attribute__ ((aligned (16))); char buf2[32] __attribute__ ((aligned (16))); @@ -464,6 +470,7 @@ test_strncat (void) } } } +#endif } static void
From: Mahesh Bodapati <bmahi496@linux.ibm.com> When building with fortify enabled, GCC < 12 issues a warning on the fortify strncat wrapper might overflow the destination buffer. However, GCC does not provide a specific flag to disable the warning (the failure is tied to -Werror). So to avoid disable all errors, only enable the check for GCC 12 or newer. Checked on ppc64 and x86_64. --- string/tester.c | 7 +++++++ 1 file changed, 7 insertions(+)