From: Wang Haoran haoranwangsec@gmail.com

commit 27e06650a5eafe832a90fd2604f0c5e920857fae upstream.

A buffer overflow arises from the usage of snprintf to write into the buffer "buf" in target_lu_gp_members_show function located in /drivers/target/target_core_configfs.c. This buffer is allocated with size LU_GROUP_NAME_BUF (256 bytes).

snprintf(...) formats multiple strings into buf with the HBA name (hba->hba_group.cg_item), a slash character, a devicename (dev-> dev_group.cg_item) and a newline character, the total formatted string length may exceed the buffer size of 256 bytes.

Since snprintf() returns the total number of bytes that would have been written (the length of %s/%sn ), this value may exceed the buffer length (256 bytes) passed to memcpy(), this will ultimately cause function memcpy reporting a buffer overflow error.

An additional check of the return value of snprintf() can avoid this buffer overflow.

Reported-by: Wang Haoran haoranwangsec@gmail.com Reported-by: ziiiro yuanmingbuaa@gmail.com Signed-off-by: Wang Haoran haoranwangsec@gmail.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com [Andrey Troshin: patch adaptation for linux-5.10] Signed-off-by: Andrey Troshin drtrosh@yandex-team.ru --- Backport fix for CVE-2025-39998 Link: https://nvd.nist.gov/vuln/detail/CVE-2025-39998 --- drivers/target/target_core_configfs.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c index 4d2fbe1429b6..e6996428c07d 100644 --- a/drivers/target/target_core_configfs.c +++ b/drivers/target/target_core_configfs.c @@ -2637,7 +2637,7 @@ static ssize_t target_lu_gp_members_show(struct config_item *item, char *page) config_item_name(&dev->dev_group.cg_item)); cur_len++; /* Extra byte for NULL terminator */

- if ((cur_len + len) > PAGE_SIZE) { + if ((cur_len + len) > PAGE_SIZE || cur_len > LU_GROUP_NAME_BUF) { pr_warn("Ran out of lu_gp_show_attr" "_members buffer\n"); break;