From ee92fa443358f4fc0017c1d0d325c27b37802504 Mon Sep 17 00:00:00 2001 From: Chen Zhongjin Date: Thu, 9 Mar 2023 16:02:30 +0800 Subject: ftrace: Fix invalid address access in lookup_rec() when index is 0 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-chenzhongjin@huawei.com Cc: stable@vger.kernel.org Fixes: 9644302e3315 ("ftrace: Speed up search by skipping pages by address") Suggested-by: Steven Rostedt (Google) Signed-off-by: Chen Zhongjin Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 750aa3f08b25..a47f7d93e32d 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1537,7 +1537,8 @@ 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, -- cgit v1.2.3 From 8732565549011cabbea08329a1aefd78a68d96c7 Mon Sep 17 00:00:00 2001 From: Tom Rix Date: Sat, 11 Mar 2023 08:51:13 -0500 Subject: ftrace: Set direct_ops storage-class-specifier to static smatch reports this warning kernel/trace/ftrace.c:2594:19: warning: symbol 'direct_ops' was not declared. Should it be static? The variable direct_ops is only used in ftrace.c, so it should be static Link: https://lore.kernel.org/linux-trace-kernel/20230311135113.711824-1-trix@redhat.com Signed-off-by: Tom Rix Acked-by: Masami Hiramatsu (Google) Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a47f7d93e32d..ec2897a76004 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -2503,7 +2503,7 @@ static void call_direct_funcs(unsigned long ip, unsigned long pip, arch_ftrace_set_direct_caller(fregs, addr); } -struct ftrace_ops direct_ops = { +static struct ftrace_ops direct_ops = { .func = call_direct_funcs, .flags = FTRACE_OPS_FL_DIRECT | FTRACE_OPS_FL_SAVE_REGS | FTRACE_OPS_FL_PERMANENT, -- cgit v1.2.3 From 2a2d8c51defb446e8d89a83f42f8e5cd529111e9 Mon Sep 17 00:00:00 2001 From: Zheng Yejian Date: Thu, 30 Mar 2023 10:52:23 +0800 Subject: ftrace: Fix issue that 'direct->addr' not restored in modify_ftrace_direct() Syzkaller report a WARNING: "WARN_ON(!direct)" in modify_ftrace_direct(). Root cause is 'direct->addr' was changed from 'old_addr' to 'new_addr' but not restored if error happened on calling ftrace_modify_direct_caller(). Then it can no longer find 'direct' by that 'old_addr'. To fix it, restore 'direct->addr' to 'old_addr' explicitly in error path. Link: https://lore.kernel.org/linux-trace-kernel/20230330025223.1046087-1-zhengyejian1@huawei.com Cc: stable@vger.kernel.org Cc: Cc: Cc: Cc: Fixes: 8a141dd7f706 ("ftrace: Fix modify_ftrace_direct.") Signed-off-by: Zheng Yejian Signed-off-by: Steven Rostedt (Google) --- kernel/trace/ftrace.c | 15 +++++++++------ 1 file changed, 9 insertions(+), 6 deletions(-) (limited to 'kernel/trace/ftrace.c') diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index 0feea145bb29..c67bcc89a771 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -5667,12 +5667,15 @@ int modify_ftrace_direct(unsigned long ip, ret = 0; } - if (unlikely(ret && new_direct)) { - direct->count++; - list_del_rcu(&new_direct->next); - synchronize_rcu_tasks(); - kfree(new_direct); - ftrace_direct_func_count--; + if (ret) { + direct->addr = old_addr; + if (unlikely(new_direct)) { + direct->count++; + list_del_rcu(&new_direct->next); + synchronize_rcu_tasks(); + kfree(new_direct); + ftrace_direct_func_count--; + } } out_unlock: -- cgit v1.2.3