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git/compat/setenv.c
Jeff King 50a6c8efa2 use st_add and st_mult for allocation size computation
If our size computation overflows size_t, we may allocate a
much smaller buffer than we expected and overflow it. It's
probably impossible to trigger an overflow in most of these
sites in practice, but it is easy enough convert their
additions and multiplications into overflow-checking
variants. This may be fixing real bugs, and it makes
auditing the code easier.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
2016-02-22 14:51:09 -08:00

40 lines
862 B
C

#include "../git-compat-util.h"
int gitsetenv(const char *name, const char *value, int replace)
{
int out;
size_t namelen, valuelen;
char *envstr;
if (!name || strchr(name, '=') || !value) {
errno = EINVAL;
return -1;
}
if (!replace) {
char *oldval = NULL;
oldval = getenv(name);
if (oldval) return 0;
}
namelen = strlen(name);
valuelen = strlen(value);
envstr = malloc(st_add3(namelen, valuelen, 2));
if (!envstr) {
errno = ENOMEM;
return -1;
}
memcpy(envstr, name, namelen);
envstr[namelen] = '=';
memcpy(envstr + namelen + 1, value, valuelen);
envstr[namelen + valuelen + 1] = 0;
out = putenv(envstr);
/* putenv(3) makes the argument string part of the environment,
* and changing that string modifies the environment --- which
* means we do not own that storage anymore. Do not free
* envstr.
*/
return out;
}