Subject: + pagemap-fix-buffer-overflow-in-add_page_map.patch added to -mm tree To: younghua.zheng@xxxxxxxxx From: akpm@xxxxxxxxxxxxxxxxxxxx Date: Mon, 12 Aug 2013 16:05:45 -0700 The patch titled Subject: fs/proc/task_mmu.c: fix buffer overflow in add_page_map() has been added to the -mm tree. Its filename is pagemap-fix-buffer-overflow-in-add_page_map.patch This patch should soon appear at http://ozlabs.org/~akpm/mmots/broken-out/pagemap-fix-buffer-overflow-in-add_page_map.patch and later at http://ozlabs.org/~akpm/mmotm/broken-out/pagemap-fix-buffer-overflow-in-add_page_map.patch Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/SubmitChecklist when testing your code *** The -mm tree is included into linux-next and is updated there every 3-4 working days ------------------------------------------------------ From: yonghua zheng <younghua.zheng@xxxxxxxxx> Subject: fs/proc/task_mmu.c: fix buffer overflow in add_page_map() Recently we met quite a lot of random kernel panic issues after enabling CONFIG_PROC_PAGE_MONITOR. After debuggind we found this has something to do with following bug in pagemap: In struct pagemapread: struct pagemapread { int pos, len; pagemap_entry_t *buffer; bool v2; }; pos is number of PM_ENTRY_BYTES in buffer, but len is the size of buffer, it is a mistake to compare pos and len in add_page_map() for checking buffer is full or not, and this can lead to buffer overflow and random kernel panic issue. Correct len to be total number of PM_ENTRY_BYTES in buffer. Signed-off-by: Yonghua Zheng <younghua.zheng@xxxxxxxxx> Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> --- fs/proc/task_mmu.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff -puN fs/proc/task_mmu.c~pagemap-fix-buffer-overflow-in-add_page_map fs/proc/task_mmu.c --- a/fs/proc/task_mmu.c~pagemap-fix-buffer-overflow-in-add_page_map +++ a/fs/proc/task_mmu.c @@ -1127,8 +1127,8 @@ static ssize_t pagemap_read(struct file goto out_task; pm.v2 = soft_dirty_cleared; - pm.len = PM_ENTRY_BYTES * (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); - pm.buffer = kmalloc(pm.len, GFP_TEMPORARY); + pm.len = (PAGEMAP_WALK_SIZE >> PAGE_SHIFT); + pm.buffer = kmalloc(pm.len * PM_ENTRY_BYTES, GFP_TEMPORARY); ret = -ENOMEM; if (!pm.buffer) goto out_task; _ Patches currently in -mm which might be from younghua.zheng@xxxxxxxxx are pagemap-fix-buffer-overflow-in-add_page_map.patch pagemap-fix-buffer-overflow-in-add_page_map-fix.patch -- To unsubscribe from this list: send the line "unsubscribe mm-commits" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html