@@ -253,6 +253,7 @@ static ssize_t snd_info_entry_write(stru
struct snd_info_buffer *buf;
ssize_t size = 0;
loff_t pos;
+ unsigned long realloc_size;
data = file->private_data;
if (snd_BUG_ON(!data))
@@ -261,7 +262,8 @@ static ssize_t snd_info_entry_write(stru
pos = *offset;
if (pos < 0 || (long) pos != pos || (ssize_t) count < 0)
return -EIO;
- if ((unsigned long) pos + (unsigned long) count < (unsigned long) pos)
+ realloc_size = (unsigned long) pos + (unsigned long) count;
+ if (realloc_size < (unsigned long) pos || realloc_size > UINT_MAX)
return -EIO;
switch (entry->content) {
case SNDRV_INFO_CONTENT_TEXT:
This is a note to let you know that I've just added the patch titled ALSA: info: Check for integer overflow in snd_info_entry_write() to the 3.18-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: alsa-info-check-for-integer-overflow-in-snd_info_entry_write.patch and it can be found in the queue-3.18 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let <stable@vger.kernel.org> know about it. From erickreyes@google.com Thu Aug 16 12:07:22 2018 From: Erick Reyes <erickreyes@google.com> Date: Wed, 15 Aug 2018 17:55:48 -0700 Subject: ALSA: info: Check for integer overflow in snd_info_entry_write() To: stable@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Jaroslav Kysela <perex@perex.cz>, Takashi Iwai <tiwai@suse.com>, kernel-team@android.com, Vinod Koul <vkoul@kernel.org>, Joe Perches <joe@perches.com>, Al Viro <viro@zeniv.linux.org.uk>, alsa-devel@alsa-project.org, Erick Reyes <erickreyes@google.com>, Siqi Lin <siqilin@google.com> Message-ID: <20180816005548.151269-1-erickreyes@google.com> From: Erick Reyes <erickreyes@google.com> Commit 4adb7bcbcb69 ("ALSA: core: Use seq_file for text proc file reads") heavily refactored ALSA procfs and fixed the overflow as a side-effect, so this fix only applies to kernels < 4.2 and there is no upstream equivalent snd_info_entry_write() resizes the buffer with an unsigned long size argument that gets truncated because resize_info_buffer() takes the size parameter as an unsigned int. On 64-bit kernels, this causes the following copy_to_user() to write out-of-bounds if (pos + count) can't be represented by an unsigned int. Signed-off-by: Siqi Lin <siqilin@google.com> Signed-off-by: Erick Reyes <erickreyes@google.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> --- sound/core/info.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) Patches currently in stable-queue which might be from erickreyes@google.com are queue-3.18/alsa-info-check-for-integer-overflow-in-snd_info_entry_write.patch