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authorJoseph Myers <joseph@codesourcery.com>2015-12-04 20:36:28 +0000
committerJoseph Myers <joseph@codesourcery.com>2015-12-04 20:36:28 +0000
commit8f5e8b01a1da2a207228f2072c934fa5918554b8 (patch)
treec9d9d33b21af5a9df86f398d2d1fd6b42eee1e28 /math/s_nanf.c
parent79e0d340a9e7fb2c931686462131c92b99611003 (diff)
downloadglibc-8f5e8b01a1da2a207228f2072c934fa5918554b8.tar.gz
Fix nan functions handling of payload strings (bug 16961, bug 16962).
The nan, nanf and nanl functions handle payload strings by doing e.g.: if (tagp[0] != '\0') { char buf[6 + strlen (tagp)]; sprintf (buf, "NAN(%s)", tagp); return strtod (buf, NULL); } This is an unbounded stack allocation based on the length of the argument. Furthermore, if the argument starts with an n-char-sequence followed by ')', that n-char-sequence is wrongly treated as significant for determining the payload of the resulting NaN, when ISO C says the call should be equivalent to strtod ("NAN", NULL), without being affected by that initial n-char-sequence. This patch fixes both those problems by using the __strtod_nan etc. functions recently factored out of strtod etc. for that purpose, with those functions being exported from libc at version GLIBC_PRIVATE. Tested for x86_64, x86, mips64 and powerpc. [BZ #16961] [BZ #16962] * math/s_nan.c (__nan): Use __strtod_nan instead of constructing a string on the stack for strtod. * math/s_nanf.c (__nanf): Use __strtof_nan instead of constructing a string on the stack for strtof. * math/s_nanl.c (__nanl): Use __strtold_nan instead of constructing a string on the stack for strtold. * stdlib/Versions (libc): Add __strtof_nan, __strtod_nan and __strtold_nan to GLIBC_PRIVATE. * math/test-nan-overflow.c: New file. * math/test-nan-payload.c: Likewise. * math/Makefile (tests): Add test-nan-overflow and test-nan-payload.
Diffstat (limited to 'math/s_nanf.c')
-rw-r--r--math/s_nanf.c9
1 files changed, 1 insertions, 8 deletions
diff --git a/math/s_nanf.c b/math/s_nanf.c
index 2d3fcc5803..6a98422e6c 100644
--- a/math/s_nanf.c
+++ b/math/s_nanf.c
@@ -28,13 +28,6 @@
float
__nanf (const char *tagp)
{
- if (tagp[0] != '\0')
- {
- char buf[6 + strlen (tagp)];
- sprintf (buf, "NAN(%s)", tagp);
- return strtof (buf, NULL);
- }
-
- return NAN;
+ return __strtof_nan (tagp, NULL, 0);
}
weak_alias (__nanf, nanf)