From: Sergey Shtylyov s.shtylyov@omp.ru
commit cf7385cb26ac4f0ee6c7385960525ad534323252 upstream.
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: Greg Kroah-Hartman gregkh@linuxfoundation.org Signed-off-by: Uwe Kleine-König ukleinek@debian.org --- 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 7fb870097a84..ee3467730dac 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -213,14 +213,15 @@ 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: 2c8115e4757809ffd537ed9108da115026d3581f
[ 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) 6.1.y | Present (different SHA1: 5d59fd637a8a) 5.15.y | Present (different SHA1: 5bdbbfb49bec) 5.10.y | Present (different SHA1: 6df2777b9e01)
Note: The patch differs from the upstream commit: --- 1: cf7385cb26ac4 ! 1: c4addef3bafbd of: module: add buffer overflow check in of_modalias() @@ Metadata ## Commit message ## of: module: add buffer overflow check in of_modalias()
+ commit cf7385cb26ac4f0ee6c7385960525ad534323252 upstream. + 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: Greg Kroah-Hartman gregkh@linuxfoundation.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-5.4.y | Success | Success |
linux-stable-mirror@lists.linaro.org
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Sasha Levin -
Uwe Kleine-König