From: Chen Zhongjin chenzhongjin@huawei.com
mainline inclusion from mainline-v6.3-rc2 commit ee92fa443358f4fc0017c1d0d325c27b37802504 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6NJNA CVE: NA
Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...
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KASAN reported follow problem:
BUG: KASAN: use-after-free in lookup_rec Read of size 8 at addr ffff000199270ff0 by task modprobe CPU: 2 Comm: modprobe Call trace: kasan_report __asan_load8 lookup_rec ftrace_location arch_check_ftrace_location check_kprobe_address_safe register_kprobe
When checking pg->records[pg->index - 1].ip in lookup_rec(), it can get a pg which is newly added to ftrace_pages_start in ftrace_process_locs(). Before the first pg->index++, index is 0 and accessing pg->records[-1].ip will cause this problem.
Don't check the ip when pg->index is 0.
Link: https://lore.kernel.org/linux-trace-kernel/20230309080230.36064-1-chenzhongj...
Cc: stable@vger.kernel.org Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address") Suggested-by: Steven Rostedt (Google) rostedt@goodmis.org Signed-off-by: Chen Zhongjin chenzhongjin@huawei.com Signed-off-by: Steven Rostedt (Google) rostedt@goodmis.org Reviewed-by: Zheng Yejian zhengyejian1@huawei.com Signed-off-by: Jialin Zhang zhangjialin11@huawei.com --- kernel/trace/ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 16388295696c..b09a9a9b49b4 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1538,7 +1538,8 @@ static struct dyn_ftrace *lookup_rec(unsigned long start, unsigned long end) key.flags = end; /* overload flags, as it is unsigned long */
for (pg = ftrace_pages_start; pg; pg = pg->next) { - if (end < pg->records[0].ip || + if (pg->index == 0 || + end < pg->records[0].ip || start >= (pg->records[pg->index - 1].ip + MCOUNT_INSN_SIZE)) continue; rec = bsearch(&key, pg->records, pg->index,