From: Dan Carpenter <dan.carpenter@oracle.com> stable inclusion from stable-v5.10.150 commit 2fee0dbfaeaaa4bda04279ce772c4572b1429d04 category: bugfix bugzilla: https://gitee.com/openeuler/kernel/issues/I6D0XA Reference: https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git/commit/?id=... -------------------------------- [ 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@oracle.com> Reviewed-by: Robin Murphy <robin.murphy@arm.com> Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com> Link: https://lore.kernel.org/r/YuvYh1JbE3v+abd5@kili Signed-off-by: Joerg Roedel <jroedel@suse.de> Signed-off-by: Sasha Levin <sashal@kernel.org> Signed-off-by: Jialin Zhang <zhangjialin11@huawei.com> --- drivers/iommu/omap-iommu-debug.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) 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 -- 2.25.1