From 50cd06b484bb99bfacdd4f9d2f8ee5e52bfc7bd3 Mon Sep 17 00:00:00 2001 From: Wu Guanghao Date: Sat, 4 Mar 2023 00:21:33 +0800 Subject: [PATCH 096/120] isuper-intel.c: fix double free in load_imsm_mpb() In load_imsm_mpb() there is potential double free issue on super->buf. The first location to free super->buf is from get_super_block() <== load_and_parse_mpb() <== load_imsm_mpb(): 4514 if (posix_memalign(&super->migr_rec_buf, MAX_SECTOR_SIZE, 4515 MIGR_REC_BUF_SECTORS*MAX_SECTOR_SIZE) != 0) { 4516 pr_err("could not allocate migr_rec buffer\n"); 4517 free(super->buf); 4518 return 2; 4519 } If the above error condition happens, super->buf is freed and value 2 is returned to get_super_block() eventually. Then in the following code block inside load_imsm_mpb(), 5289 error: 5290 if (!err) { 5291 s->next = *super_list; 5292 *super_list = s; 5293 } else { 5294 if (s) 5295 free_imsm(s); 5296 close_fd(&dfd); 5297 } at line 5295 when free_imsm() is called, super->buf is freed again from the call chain free_imsm() <== __free_imsm(), in following code block, 4651 if (super->buf) { 4652 free(super->buf); 4653 super->buf = NULL; 4654 } This patch sets super->buf as NULL after line 4517 in load_imsm_mpb() to avoid the potential double free(). (Coly Li helps to re-compose the commit log) Signed-off-by: Wu Guanghao Reviewed-by: Mariusz Tkaczyk Acked-by: Coly Li Signed-off-by: Jes Sorensen --- super-intel.c | 1 + 1 file changed, 1 insertion(+) diff --git a/super-intel.c b/super-intel.c index 89fac626..4a3da847 100644 --- a/super-intel.c +++ b/super-intel.c @@ -4515,6 +4515,7 @@ static int load_imsm_mpb(int fd, struct intel_super *super, char *devname) MIGR_REC_BUF_SECTORS*MAX_SECTOR_SIZE) != 0) { pr_err("could not allocate migr_rec buffer\n"); free(super->buf); + super->buf = NULL; return 2; } super->clean_migration_record_by_mdmon = 0; -- 2.38.1