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* [gcc r14-3457] libstdc++: fix illegal pointer arithmetic in format [PR111102]
@ 2023-08-24 12:45 Jonathan Wakely
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From: Jonathan Wakely @ 2023-08-24 12:45 UTC (permalink / raw)
To: gcc-cvs, libstdc++-cvs
https://gcc.gnu.org/g:dd4bdb9eea436bf06f175d8dbfc2190377455be4
commit r14-3457-gdd4bdb9eea436bf06f175d8dbfc2190377455be4
Author: Paul Dreik <gccpatches@pauldreik.se>
Date: Thu Aug 24 11:43:43 2023 +0100
libstdc++: fix illegal pointer arithmetic in format [PR111102]
When parsing a format string, the width is parsed into an unsigned short
but the result is not checked in the case the format string is not a
char string (such as a wide string). In case the parse fails, a null
pointer is returned which is used for pointer arithmetic which is
undefined behaviour.
Signed-off-by: Paul Dreik <gccpatches@pauldreik.se>
libstdc++-v3/ChangeLog:
PR libstdc++/111102
* include/std/format (__format::__parse_integer): Check for
non-null pointer.
Diff:
---
libstdc++-v3/include/std/format | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/libstdc++-v3/include/std/format b/libstdc++-v3/include/std/format
index f3d9ae152f90..fe2caa586881 100644
--- a/libstdc++-v3/include/std/format
+++ b/libstdc++-v3/include/std/format
@@ -285,7 +285,8 @@ namespace __format
for (int __i = 0; __i < __n && (__first + __i) != __last; ++__i)
__buf[__i] = __first[__i];
auto [__v, __ptr] = __format::__parse_integer(__buf, __buf + __n);
- return {__v, __first + (__ptr - __buf)};
+ if (__ptr) [[likely]]
+ return {__v, __first + (__ptr - __buf)};
}
return {0, nullptr};
}
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