From: "Steven Rostedt (VMware)" rostedt@goodmis.org
stable inclusion from stable-v5.10.44 commit 97524384762c1fb9b3ded931498dd2047bd0de81 bugzilla: https://bugzilla.openeular.org/show_bug.cgi?id=429 CVE: NA
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commit 6c14133d2d3f768e0a35128faac8aa6ed4815051 upstream.
It was reported that a bug on arm64 caused a bad ip address to be used for updating into a nop in ftrace_init(), but the error path (rightfully) returned -EINVAL and not -EFAULT, as the bug caused more than one error to occur. But because -EINVAL was returned, the ftrace_bug() tried to report what was at the location of the ip address, and read it directly. This caused the machine to panic, as the ip was not pointing to a valid memory address.
Instead, read the ip address with copy_from_kernel_nofault() to safely access the memory, and if it faults, report that the address faulted, otherwise report what was in that location.
Link: https://lore.kernel.org/lkml/20210607032329.28671-1-mark-pk.tsai@mediatek.co...
Cc: stable@vger.kernel.org Fixes: 05736a427f7e1 ("ftrace: warn on failure to disable mcount callers") Reported-by: Mark-PK Tsai mark-pk.tsai@mediatek.com Tested-by: Mark-PK Tsai mark-pk.tsai@mediatek.com Signed-off-by: Steven Rostedt (VMware) rostedt@goodmis.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: fzy fzy_caesar_0910@163.com Reviewed-by: Jian Cheng <cj.chengjian(a)huawei.com> Signed-off-by: Wang ShaoBo bobo.shaobowang@huawei.com --- kernel/trace/ftrace.c | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-)
diff --git a/kernel/trace/ftrace.c b/kernel/trace/ftrace.c index a6d15a3187d0..30010614b923 100644 --- a/kernel/trace/ftrace.c +++ b/kernel/trace/ftrace.c @@ -1968,12 +1968,18 @@ static int ftrace_hash_ipmodify_update(struct ftrace_ops *ops,
static void print_ip_ins(const char *fmt, const unsigned char *p) { + char ins[MCOUNT_INSN_SIZE]; int i;
+ if (copy_from_kernel_nofault(ins, p, MCOUNT_INSN_SIZE)) { + printk(KERN_CONT "%s[FAULT] %px\n", fmt, p); + return; + } + printk(KERN_CONT "%s", fmt);
for (i = 0; i < MCOUNT_INSN_SIZE; i++) - printk(KERN_CONT "%s%02x", i ? ":" : "", p[i]); + printk(KERN_CONT "%s%02x", i ? ":" : "", ins[i]); }
enum ftrace_bug_type ftrace_bug_type;