[lvc-project] [PATCH 5.10] scsi: target: target_core_configfs: Add length check to avoid buffer overflow

[Andrey Troshin]

scsi: target: target_core_configfs: Add length check to avoid buffer overflow
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 ÎÁ gmail.com>
Reported-by: ziiiro <yuanmingbuaa ÎÁ gmail.com>
Signed-off-by: Wang Haoran <haoranwangsec ÎÁ gmail.com>
Signed-off-by: Martin K. Petersen <martin.petersen ÎÁ oracle.com>
[Andrey Troshin: patch adaptation for linux-5.10]
Signed-off-by: Andrey Troshin <drtrosh ÎÁ 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;
-- 
2.34.1