From: Sergey Shtylyov s.shtylyov@omp.ru

mainline inclusion from mainline-v6.10-rc1 commit cf7385cb26ac4f0ee6c7385960525ad534323252 category: bugfix bugzilla: https://gitee.com/src-openeuler/kernel/issues/IA6SDQ CVE: CVE-2024-38541

Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?i...

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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 Conflicts: drivers/of/device.c [of_modalias() was in drivers/of/device.c before commit bd7a7ed774af ("of: Move of_modalias() to module.c") and was named as of_device_get_modalias() before commit 5c3d15e127eb ("of: Update of_device_get_modalias()"). Both commits are in v6.4.] Signed-off-by: GONG, Ruiqi gongruiqi1@huawei.com --- 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 566d8af05157..65235ff63c5d 100644 --- a/drivers/of/device.c +++ b/drivers/of/device.c @@ -225,14 +225,15 @@ 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', dev->of_node->type); 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);