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| author | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-10-11 14:22:35 +0100 |
|---|---|---|
| committer | Szabolcs Nagy <szabolcs.nagy@arm.com> | 2022-10-28 11:16:09 +0100 |
| commit | eef17d4d9fcd38c5cbb9bc9515ba72d1773b67a2 (patch) | |
| tree | b7b53fe307a94d583aa7681a7b0d7653c45a3e02 /elf | |
| parent | 68619ddb3b7e8b64a6b849e4972e67163f7659c3 (diff) | |
| download | glibc-eef17d4d9fcd38c5cbb9bc9515ba72d1773b67a2.zip glibc-eef17d4d9fcd38c5cbb9bc9515ba72d1773b67a2.tar.gz glibc-eef17d4d9fcd38c5cbb9bc9515ba72d1773b67a2.tar.bz2 | |
elf: Fix alloca size in _dl_debug_vdprintf
The alloca size did not consider the optional width parameter for
padding which could cause buffer underflow. The width is currently used
e.g. by _dl_map_object_from_fd which passes 2 * sizeof(void *) which
can be larger than the alloca buffer size on targets where
sizeof(void *) >= 2 * sizeof(unsigned long).
Even if large width is not used on existing targets it is better to fix
the formatting code to avoid surprises.
Reviewed-by: Florian Weimer <fweimer@redhat.com>
Diffstat (limited to 'elf')
| -rw-r--r-- | elf/dl-printf.c | 7 |
1 files changed, 5 insertions, 2 deletions
diff --git a/elf/dl-printf.c b/elf/dl-printf.c index 429d2e8..00c1140 100644 --- a/elf/dl-printf.c +++ b/elf/dl-printf.c @@ -163,8 +163,11 @@ _dl_debug_vdprintf (int fd, int tag_p, const char *fmt, va_list arg) /* We use alloca() to allocate the buffer with the most pessimistic guess for the size. Using alloca() allows having more than one integer formatting in a call. */ - char *buf = (char *) alloca (1 + 3 * sizeof (unsigned long int)); - char *endp = &buf[1 + 3 * sizeof (unsigned long int)]; + int size = 1 + 3 * sizeof (unsigned long int); + if (width + 1 > size) + size = width + 1; + char *buf = (char *) alloca (size); + char *endp = &buf[size]; char *cp = _itoa (num, endp, *fmt == 'x' ? 16 : 10, 0); /* Pad to the width the user specified. */ |