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lavu/mem: fix potential int overflow and crash in av_dynarray_add()

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Also extend documentation accordingly.
This commit is contained in:
Stefano Sabatini 2013-04-25 00:27:46 +02:00
parent c773adee3f
commit ee9794ed20
2 changed files with 14 additions and 2 deletions
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14
libavutil/mem.c
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@ -249,15 +249,25 @@ void av_dynarray_add(void *tab_ptr, int *nb_ptr, void *elem)
nb = *nb_ptr;
tab = *(intptr_t**)tab_ptr;
if ((nb & (nb - 1)) == 0) {
if (nb == 0)
if (nb == 0) {
nb_alloc = 1;
else
} else {
if (nb > INT_MAX / (2 * sizeof(intptr_t)))
goto fail;
nb_alloc = nb * 2;
}
tab = av_realloc(tab, nb_alloc * sizeof(intptr_t));
if (!tab)
goto fail;
*(intptr_t**)tab_ptr = tab;
}
tab[nb++] = (intptr_t)elem;
*nb_ptr = nb;
return;
fail:
av_freep(tab_ptr);
*nb_ptr = 0;
}
static void fill16(uint8_t *dst, int len)

2
libavutil/mem.h
View File

@ -209,6 +209,8 @@ void av_freep(void *ptr);
* In case of success, the pointer to the array is updated in order to
* point to the new grown array, and the number pointed to by nb_ptr
* is incremented.
* In case of failure, the array is freed, *tab_ptr is set to NULL and
* *nb_ptr is set to 0.
*
* @param tab_ptr pointer to the array to grow
* @param nb_ptr pointer to the number of elements in the array