Messages in this thread Patch in this message |  | | From | <> | Subject | [PATCH v3 1/2] printk: Fix panic caused by passing log_buf_len to command line | Date | Sat, 22 Sep 2018 23:40:51 +0800 |
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From: He Zhe <zhe.he@windriver.com>
log_buf_len_setup does not check input argument before passing it to simple_strtoull. The argument would be a NULL pointer if "log_buf_len", without its value, is set in command line and thus causes the following panic.
PANIC: early exception 0xe3 IP 10:ffffffffaaeacd0d error 0 cr2 0x0 [ 0.000000] CPU: 0 PID: 0 Comm: swapper Not tainted 4.19.0-rc4-yocto-standard+ #1 [ 0.000000] RIP: 0010:_parse_integer_fixup_radix+0xd/0x70 ... [ 0.000000] Call Trace: [ 0.000000] simple_strtoull+0x29/0x70 [ 0.000000] memparse+0x26/0x90 [ 0.000000] log_buf_len_setup+0x17/0x22 [ 0.000000] do_early_param+0x57/0x8e [ 0.000000] parse_args+0x208/0x320 [ 0.000000] ? rdinit_setup+0x30/0x30 [ 0.000000] parse_early_options+0x29/0x2d [ 0.000000] ? rdinit_setup+0x30/0x30 [ 0.000000] parse_early_param+0x36/0x4d [ 0.000000] setup_arch+0x336/0x99e [ 0.000000] start_kernel+0x6f/0x4ee [ 0.000000] x86_64_start_reservations+0x24/0x26 [ 0.000000] x86_64_start_kernel+0x6f/0x72 [ 0.000000] secondary_startup_64+0xa4/0xb0
This patch adds a check to prevent the panic.
Signed-off-by: He Zhe <zhe.he@windriver.com> Cc: stable@vger.kernel.org Cc: pmladek@suse.com Cc: sergey.senozhatsky@gmail.com Cc: rostedt@goodmis.org --- v2: Split out the addition of pr_fmt and the unsigned update v3: Use more clear error info Change unsigned to unsigned in to avoid checkpatch.pl warning
kernel/printk/printk.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-)
diff --git a/kernel/printk/printk.c b/kernel/printk/printk.c index 9bf5404..d9821c0 100644 --- a/kernel/printk/printk.c +++ b/kernel/printk/printk.c @@ -1048,7 +1048,14 @@ static void __init log_buf_len_update(unsigned size) /* save requested log_buf_len since it's too early to process it */ static int __init log_buf_len_setup(char *str) { - unsigned size = memparse(str, &str); + unsigned int size; + + if (!str) { + pr_err("boot command line parameter value not provided\n"); + return -EINVAL; + } + + size = memparse(str, &str); log_buf_len_update(size); -- 2.7.4
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