This is a note to let you know that I've just added the patch titled
iommu/omap: Fix buffer overflow in debugfs
to the 5.15-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:
iommu-omap-fix-buffer-overflow-in-debugfs.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit f8111244b70af64594e0bff446effc588bf361bb
Author: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Date: Thu Aug 4 17:32:39 2022 +0300
iommu/omap: Fix buffer overflow in debugfs
[ Upstream commit 184233a5202786b20220acd2d04ddf909ef18f29 ]
There are two issues here:
1) The "len" variable needs to be checked before the very first write.
Otherwise if omap2_iommu_dump_ctx() with "bytes" less than 32 it is a
buffer overflow.
2) The snprintf() function returns the number of bytes that *would* have
been copied if there were enough space. But we want to know the
number of bytes which were *actually* copied so use scnprintf()
instead.
Fixes: bd4396f09a4a ("iommu/omap: Consolidate OMAP IOMMU modules")
Signed-off-by: Dan Carpenter <dan.carpenter@xxxxxxxxxx>
Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
Reviewed-by: Laurent Pinchart <laurent.pinchart@xxxxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/YuvYh1JbE3v+abd5@kili
Signed-off-by: Joerg Roedel <jroedel@xxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/iommu/omap-iommu-debug.c b/drivers/iommu/omap-iommu-debug.c
index a99afb5d9011..259f65291d90 100644
--- a/drivers/iommu/omap-iommu-debug.c
+++ b/drivers/iommu/omap-iommu-debug.c
@@ -32,12 +32,12 @@ static inline bool is_omap_iommu_detached(struct omap_iommu *obj)
ssize_t bytes; \
const char *str = "%20s: %08x\n"; \
const int maxcol = 32; \
- bytes = snprintf(p, maxcol, str, __stringify(name), \
+ if (len < maxcol) \
+ goto out; \
+ bytes = scnprintf(p, maxcol, str, __stringify(name), \
iommu_read_reg(obj, MMU_##name)); \
p += bytes; \
len -= bytes; \
- if (len < maxcol) \
- goto out; \
} while (0)
static ssize_t
