diff options
| author | Jia He <justin.he@arm.com> | 2019-08-09 09:24:56 +0800 |
|---|---|---|
| committer | Petr Mladek <pmladek@suse.com> | 2019-08-15 16:40:10 +0200 |
| commit | 36594b317c656bec8f968db93701d2cb9bc9155c (patch) | |
| tree | 4cebb6b88c3d8f37dc076b8bd219ec03f21f974f /lib | |
| parent | 7011b7e1b702cc76f9e969b41d9a95969f2aecaa (diff) | |
vsprintf: Prevent crash when dereferencing invalid pointers for %pD
Commit 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid
pointers") prevents most crash except for %pD.
There is an additional pointer dereferencing before dentry_name.
At least, vma->file can be NULL and be passed to printk %pD in
print_bad_pte, which can cause crash.
This patch fixes it with introducing a new file_dentry_name.
Link: http://lkml.kernel.org/r/20190809012457.56685-1-justin.he@arm.com
Fixes: 3e5903eb9cff ("vsprintf: Prevent crash when dereferencing invalid pointers")
To: Geert Uytterhoeven <geert+renesas@glider.be>
To: Thomas Gleixner <tglx@linutronix.de>
To: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
To: linux-kernel@vger.kernel.org
Cc: Kees Cook <keescook@chromium.org>
Cc: "Steven Rostedt (VMware)" <rostedt@goodmis.org>
Cc: Shuah Khan <shuah@kernel.org>
Cc: "Tobin C. Harding" <tobin@kernel.org>
Signed-off-by: Jia He <justin.he@arm.com>
Reviewed-by: Andy Shevchenko <andy.shevchenko@gmail.com>
Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
Signed-off-by: Petr Mladek <pmladek@suse.com>
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/vsprintf.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/lib/vsprintf.c b/lib/vsprintf.c index b0967cf17137..e78017a3e1bd 100644 --- a/lib/vsprintf.c +++ b/lib/vsprintf.c @@ -869,6 +869,15 @@ char *dentry_name(char *buf, char *end, const struct dentry *d, struct printf_sp return widen_string(buf, n, end, spec); } +static noinline_for_stack +char *file_dentry_name(char *buf, char *end, const struct file *f, + struct printf_spec spec, const char *fmt) +{ + if (check_pointer(&buf, end, f, spec)) + return buf; + + return dentry_name(buf, end, f->f_path.dentry, spec, fmt); +} #ifdef CONFIG_BLOCK static noinline_for_stack char *bdev_name(char *buf, char *end, struct block_device *bdev, @@ -2166,9 +2175,7 @@ char *pointer(const char *fmt, char *buf, char *end, void *ptr, case 'C': return clock(buf, end, ptr, spec, fmt); case 'D': - return dentry_name(buf, end, - ((const struct file *)ptr)->f_path.dentry, - spec, fmt); + return file_dentry_name(buf, end, ptr, spec, fmt); #ifdef CONFIG_BLOCK case 'g': return bdev_name(buf, end, ptr, spec, fmt); |