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privsep: Avoid undefined behavior in pointer arithmetic

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Reorder terms in a way that no invalid pointers are generated with
pos+len operations. end-pos is always defined (with a valid pos pointer)
while pos+len could end up pointing beyond the end pointer which would
be undefined behavior.

Signed-off-by: Jouni Malinen <j@w1.fi>
This commit is contained in:
Jouni Malinen 2015-10-18 19:08:25 +03:00
parent 45a283e6d0
commit ceb19ff7a6
1 changed files with 2 additions and 2 deletions
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4
src/drivers/driver_privsep.c
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@ -161,11 +161,11 @@ wpa_driver_privsep_get_scan_results2(void *priv)
return NULL; return NULL;
} }
while (results->num < (size_t) num && pos + sizeof(int) < end) { while (results->num < (size_t) num && end - pos > sizeof(int)) {
int len; int len;
os_memcpy(&len, pos, sizeof(int)); os_memcpy(&len, pos, sizeof(int));
pos += sizeof(int); pos += sizeof(int);
if (len < 0 || len > 10000 || pos + len > end) if (len < 0 || len > 10000 || len > end - pos)
break; break;
r = os_malloc(len); r = os_malloc(len);