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0048-ps/output.c: Make sure all escape*() arguments are safe.

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The SECURE_ESCAPE_ARGS() macro solves several potential problems
(although we found no problematic calls to the escape*() functions in
procps's code-base, but had to thoroughly review every call; and this is
library code):

1/ off-by-one overflows if the size of the destination buffer is 0;

2/ buffer overflows if this size (or "maxroom") is negative;

3/ integer overflows (for example, "*maxcells+1");

4/ always null-terminate the destination buffer (unless its size is 0).

---------------------------- adapted for newlib branch
. formerly applied to proc/escape.c
. function was moved to ps/output.c

Signed-off-by: Jim Warner <james.warner@comcast.net>
This commit is contained in:
Qualys Security Advisory - committed by Craig Small
parent f0b245c794
commit f44fe715bd
1 changed files with 10 additions and 0 deletions
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10
ps/output.c
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@ -110,9 +110,19 @@ static void get_memory_total()
procps_meminfo_unref(&mem_info); procps_meminfo_unref(&mem_info);
} }
#define SECURE_ESCAPE_ARGS(dst, bytes, cells) do { \
if ((bytes) <= 0) return 0; \
*(dst) = '\0'; \
if ((bytes) >= INT_MAX) return 0; \
if ((cells) >= INT_MAX) return 0; \
if ((cells) <= 0) return 0; \
} while (0)
// copy an already 'escaped' string, // copy an already 'escaped' string,
static int escaped_copy(char *restrict dst, const char *restrict src, int bufsize, int *maxroom){ static int escaped_copy(char *restrict dst, const char *restrict src, int bufsize, int *maxroom){
int n; int n;
SECURE_ESCAPE_ARGS(dst, bufsize, *maxroom);
if (bufsize > *maxroom+1) if (bufsize > *maxroom+1)
bufsize = *maxroom+1; bufsize = *maxroom+1;
n = snprintf(dst, bufsize, "%s", src); n = snprintf(dst, bufsize, "%s", src);