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
[ Sasha's backport helper bot ]
Hi,
✅ All tests passed successfully. No issues detected. No action required from the submitter.
The upstream commit SHA1 provided is correct: cf7385cb26ac4f0ee6c7385960525ad534323252
WARNING: Author mismatch between patch and upstream commit: Backport author: ukleinek@debian.org Commit author: Sergey Shtylyovs.shtylyov@omp.ru
Status in newer kernel trees: 6.14.y | Present (exact SHA1) 6.12.y | Present (exact SHA1) 6.6.y | Present (different SHA1: 0b0d5701a8bf)
Note: The patch differs from the upstream commit: --- 1: cf7385cb26ac4 ! 1: a49c07db9c584 of: module: add buffer overflow check in of_modalias() @@ Metadata ## Commit message ## of: module: add buffer overflow check in of_modalias()
+ [ 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 @@ Commit message 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
- ## drivers/of/module.c ## -@@ drivers/of/module.c: ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len) - csize = snprintf(str, len, "of:N%pOFn%c%s", np, 'T', - of_node_get_device_type(np)); + ## drivers/of/device.c ## +@@ drivers/of/device.c: 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; @@ drivers/of/module.c: ssize_t of_modalias(const struct device_node *np, char *str - str += csize; + str += csize;
- of_property_for_each_string(np, "compatible", p, compat) { + of_property_for_each_string(dev->of_node, "compatible", p, compat) { csize = strlen(compat) + 1; tsize += csize; - if (csize > len) ---
Results of testing on various branches:
| Branch | Patch Apply | Build Test | |---------------------------|-------------|------------| | stable/linux-6.1.y | Success | Success |
linux-stable-mirror@lists.linaro.org
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Sasha Levin -
Uwe Kleine-König