Applied "drivers/media/platform/sti/delta/delta-ipc.c: fix read buffer overflow" to the spi tree

[Mark Brown <broonie@xxxxxxxxxx>]

The patch

   drivers/media/platform/sti/delta/delta-ipc.c: fix read buffer overflow

has been applied to the spi tree at

   https://git.kernel.org/pub/scm/linux/kernel/git/broonie/spi.git 

All being well this means that it will be integrated into the linux-next
tree (usually sometime in the next 24 hours) and sent to Linus during
the next merge window (or sooner if it is a bug fix), however if
problems are discovered then the patch may be dropped or reverted.  

You may get further e-mails resulting from automated or manual testing
and review of the tree, please engage with people reporting problems and
send followup patches addressing any issues that are reported if needed.

If any updates are required or you are submitting further changes they
should be sent as incremental updates against current git, existing
patches will not be replaced.

Please add any relevant lists and maintainers to the CCs when replying
to this mail.

Thanks,
Mark

>From 7091f070003a51244fa24d0a2eaf87312210653b Mon Sep 17 00:00:00 2001
From: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Date: Fri, 23 Mar 2018 11:29:04 +1100
Subject: [PATCH] drivers/media/platform/sti/delta/delta-ipc.c: fix read buffer
 overflow

The single caller passes a string to delta_ipc_open, which copies with a
fixed size larger than the string.  So it copies some random data after
the original string the ro segment.

If the string was at the end of a page it may fault.

Just copy the string with a normal strcpy after clearing the field.

Found by a LTO build (which errors out)
because the compiler inlines the functions and can resolve
the string sizes and triggers the compile time checks in memcpy.

In function `memcpy',
    inlined from `delta_ipc_open.constprop' at linux/drivers/media/platform/sti/delta/delta-ipc.c:178:0,
    inlined from `delta_mjpeg_ipc_open' at linux/drivers/media/platform/sti/delta/delta-mjpeg-dec.c:227:0,
    inlined from `delta_mjpeg_decode' at linux/drivers/media/platform/sti/delta/delta-mjpeg-dec.c:403:0:
/home/andi/lsrc/linux/include/linux/string.h:337:0: error: call to `__read_overflow2' declared with attribute error: detected read beyond size of object passed as 2nd parameter
    __read_overflow2();

Link: http://lkml.kernel.org/r/20171222001212.1850-1-andi@xxxxxxxxxxxxxx
Signed-off-by: Andi Kleen <ak@xxxxxxxxxxxxxxx>
Cc: Hugues FRUCHET <hugues.fruchet@xxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Stephen Rothwell <sfr@xxxxxxxxxxxxxxxx>
---
 drivers/media/platform/sti/delta/delta-ipc.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/media/platform/sti/delta/delta-ipc.c b/drivers/media/platform/sti/delta/delta-ipc.c
index a4603d573c34..bd1bbbeedec3 100644
--- a/drivers/media/platform/sti/delta/delta-ipc.c
+++ b/drivers/media/platform/sti/delta/delta-ipc.c
@@ -175,8 +175,8 @@ int delta_ipc_open(struct delta_ctx *pctx, const char *name,
 	msg.ipc_buf_size = ipc_buf_size;
 	msg.ipc_buf_paddr = ctx->ipc_buf->paddr;
 
-	memcpy(msg.name, name, sizeof(msg.name));
-	msg.name[sizeof(msg.name) - 1] = 0;
+	memset(msg.name, 0, sizeof(msg.name));
+	strcpy(msg.name, name);
 
 	msg.param_size = param->size;
 	memcpy(ctx->ipc_buf->vaddr, param->data, msg.param_size);
-- 
2.16.2

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