Bug#1103277: [PATCH 6.1.y] of: module: add buffer overflow check in of_modalias()
From: Sergey Shtylyov <s.shtylyov@omp.ru>
[ Upstream commit cf7385cb26ac4f0ee6c7385960525ad534323252 ]
In of_modalias(), if the buffer happens to be too small even for the 1st
snprintf() call, the len parameter will become negative and str parameter
(if not NULL initially) will point beyond the buffer's end. Add the buffer
overflow check after the 1st snprintf() call and fix such check after the
strlen() call (accounting for the terminating NUL char).
Fixes: bc575064d688 ("of/device: use of_property_for_each_string to parse compatible strings")
Signed-off-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/bbfc6be0-c687-62b6-d015-5141b93f313e@omp.ru
Signed-off-by: Rob Herring <robh@kernel.org>
Signed-off-by: Uwe Kleine-König <ukleinek@debian.org>
---
Hello,
commit cf7385cb26ac4f0ee6c7385960525ad534323252 was already backported to
stable/linux-6.6.y as commit 0b0d5701a8bf02f8fee037e81aacf6746558bfd6.
In 6.1 the function to fix is in a different file and differently named
since v6.1 lacks commits 5c3d15e127eb ("of: Update
of_device_get_modalias()") and bd7a7ed774af ("of: Move of_modalias() to
module.c")
This is the respective backport to 6.1. Looking into that commit was
triggered by https://bugs.debian.org/1103277 and my backport is
identical to this bug's reporter's. Thanks for considering it for the
next 6.1.y update.
Best regards
Uwe
drivers/of/device.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/of/device.c b/drivers/of/device.c
index ce225d2590b5..91d92bfe5735 100644
--- a/drivers/of/device.c
+++ b/drivers/of/device.c
@@ -264,14 +264,15 @@ static ssize_t of_device_get_modalias(struct device *dev, char *str, ssize_t len
csize = snprintf(str, len, "of:N%pOFn%c%s", dev->of_node, 'T',
of_node_get_device_type(dev->of_node));
tsize = csize;
+ if (csize >= len)
+ csize = len > 0 ? len - 1 : 0;
len -= csize;
- if (str)
- str += csize;
+ str += csize;
of_property_for_each_string(dev->of_node, "compatible", p, compat) {
csize = strlen(compat) + 1;
tsize += csize;
- if (csize > len)
+ if (csize >= len)
continue;
csize = snprintf(str, len, "C%s", compat);
base-commit: 535ec20c50273d81b2cc7985fed2108dee0e65d7
--
2.47.2
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