From edce6820a9fdda85521211cb334a183e34cc455e Mon Sep 17 00:00:00 2001 From: Jeffrey Carlyle Date: Mon, 30 Aug 2010 19:55:09 +0200 Subject: scatterlist: prevent invalid free when alloc fails When alloc fails, free_table is being called. Depending on the number of bytes requested, we determine if we are going to call _get_free_page() or kmalloc(). When alloc fails, our math is wrong (due to sg_size - 1), and the last buffer is wrongfully assumed to have been allocated by kmalloc. Hence, kfree gets called and a panic occurs. Signed-off-by: Jeffrey Carlyle Signed-off-by: Olusanya Soyannwo Acked-by: Tejun Heo Signed-off-by: Jens Axboe --- lib/scatterlist.c | 14 ++++++++++++-- 1 file changed, 12 insertions(+), 2 deletions(-) (limited to 'lib') diff --git a/lib/scatterlist.c b/lib/scatterlist.c index a5ec428..4ceb05d 100644 --- a/lib/scatterlist.c +++ b/lib/scatterlist.c @@ -248,8 +248,18 @@ int __sg_alloc_table(struct sg_table *table, unsigned int nents, left -= sg_size; sg = alloc_fn(alloc_size, gfp_mask); - if (unlikely(!sg)) - return -ENOMEM; + if (unlikely(!sg)) { + /* + * Adjust entry count to reflect that the last + * entry of the previous table won't be used for + * linkage. Without this, sg_kfree() may get + * confused. + */ + if (prv) + table->nents = ++table->orig_nents; + + return -ENOMEM; + } sg_init_table(sg, alloc_size); table->nents = table->orig_nents += sg_size; -- cgit v1.1 From f015ac3edd84ad72f88e08a4d83c56c360aae404 Mon Sep 17 00:00:00 2001 From: Don Mullis Date: Thu, 30 Sep 2010 15:15:32 -0700 Subject: lib/list_sort: do not pass bad pointers to cmp callback If the original list is a POT in length, the first callback from line 73 will pass a==b both pointing to the original list_head. This is dangerous because the 'list_sort()' user can use 'container_of()' and accesses the "containing" object, which does not necessary exist for the list head. So the user can access RAM which does not belong to him. If this is a write access, we can end up with memory corruption. Signed-off-by: Don Mullis Tested-by: Artem Bityutskiy Signed-off-by: Artem Bityutskiy Cc: Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- lib/list_sort.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'lib') diff --git a/lib/list_sort.c b/lib/list_sort.c index 4b5cb79..a7616fa 100644 --- a/lib/list_sort.c +++ b/lib/list_sort.c @@ -70,7 +70,7 @@ static void merge_and_restore_back_links(void *priv, * element comparison is needed, so the client's cmp() * routine can invoke cond_resched() periodically. */ - (*cmp)(priv, tail, tail); + (*cmp)(priv, tail->next, tail->next); tail->next->prev = tail; tail = tail->next; -- cgit v1.1 From 5336377d6225959624146629ce3fc88ee8ecda3d Mon Sep 17 00:00:00 2001 From: Linus Torvalds Date: Tue, 5 Oct 2010 11:29:27 -0700 Subject: modules: Fix module_bug_list list corruption race With all the recent module loading cleanups, we've minimized the code that sits under module_mutex, fixing various deadlocks and making it possible to do most of the module loading in parallel. However, that whole conversion totally missed the rather obscure code that adds a new module to the list for BUG() handling. That code was doubly obscure because (a) the code itself lives in lib/bugs.c (for dubious reasons) and (b) it gets called from the architecture-specific "module_finalize()" rather than from generic code. Calling it from arch-specific code makes no sense what-so-ever to begin with, and is now actively wrong since that code isn't protected by the module loading lock any more. So this commit moves the "module_bug_{finalize,cleanup}()" calls away from the arch-specific code, and into the generic code - and in the process protects it with the module_mutex so that the list operations are now safe. Future fixups: - move the module list handling code into kernel/module.c where it belongs. - get rid of 'module_bug_list' and just use the regular list of modules (called 'modules' - imagine that) that we already create and maintain for other reasons. Reported-and-tested-by: Thomas Gleixner Cc: Rusty Russell Cc: Adrian Bunk Cc: Andrew Morton Cc: stable@kernel.org Signed-off-by: Linus Torvalds --- lib/bug.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) (limited to 'lib') diff --git a/lib/bug.c b/lib/bug.c index 7cdfad8..1955209 100644 --- a/lib/bug.c +++ b/lib/bug.c @@ -72,8 +72,8 @@ static const struct bug_entry *module_find_bug(unsigned long bugaddr) return NULL; } -int module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, - struct module *mod) +void module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, + struct module *mod) { char *secstrings; unsigned int i; @@ -97,8 +97,6 @@ int module_bug_finalize(const Elf_Ehdr *hdr, const Elf_Shdr *sechdrs, * could potentially lead to deadlock and thus be counter-productive. */ list_add(&mod->bug_list, &module_bug_list); - - return 0; } void module_bug_cleanup(struct module *mod) -- cgit v1.1