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authorKees Cook <keescook@chromium.org>2018-03-27 14:06:14 -0700
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2018-03-28 13:23:54 +0200
commitb5b38200ebe54879a7264cb6f33821f61c586a7e (patch)
tree80880ee96abcb2a7ce8edbdca6de36d224998157 /drivers/char/mem.c
parentb24d0d5b12a678b96676348976982686fbe222b4 (diff)
/dev/mem: Avoid overwriting "err" in read_mem()
Successes in probe_kernel_read() would mask failures in copy_to_user() during read_mem(). Reported-by: Brad Spengler <spender@grsecurity.net> Fixes: 22ec1a2aea73 ("/dev/mem: Add bounce buffer for copy-out") Cc: stable@vger.kernel.org Signed-off-by: Kees Cook <keescook@chromium.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/char/mem.c')
-rw-r--r--drivers/char/mem.c6
1 files changed, 3 insertions, 3 deletions
diff --git a/drivers/char/mem.c b/drivers/char/mem.c
index 052011bcf100..ffeb60d3434c 100644
--- a/drivers/char/mem.c
+++ b/drivers/char/mem.c
@@ -137,7 +137,7 @@ static ssize_t read_mem(struct file *file, char __user *buf,
while (count > 0) {
unsigned long remaining;
- int allowed;
+ int allowed, probe;
sz = size_inside_page(p, count);
@@ -160,9 +160,9 @@ static ssize_t read_mem(struct file *file, char __user *buf,
if (!ptr)
goto failed;
- err = probe_kernel_read(bounce, ptr, sz);
+ probe = probe_kernel_read(bounce, ptr, sz);
unxlate_dev_mem_ptr(p, ptr);
- if (err)
+ if (probe)
goto failed;
remaining = copy_to_user(buf, bounce, sz);