[PATCH mtd-utils] lib: Fix integer overflow in in libiniparser.c

[Anton Moryakov]

Report of the static analyzer:
Possible integer underflow: left operand is tainted.
An integer underflow may occur due to arithmetic operation (subtraction) between values
{ [-2147483648, 2147483647] } and '1', where the first value comes from the expression '(int)strlen(line)'

Corrections explained:
Modified logic toskip empty lines immediately, reducing unnecessary processing.- Ensured safety by validating len >= 0 before accessing line[len] to avoid out-of-bounds access.

Triggers found by static analyzer Svace.

Signed-off-by: Anton Moryakov <ant.v.moryakov at gmail.co
Reviewed-by: Zhihao Cheng <chengzhihao1 at huawei.com>

---
 lib/libiniparser.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/lib/libiniparser.c b/lib/libiniparser.c
index a6ddcc7..9790c75 100644
--- a/lib/libiniparser.c
+++ b/lib/libiniparser.c
@@ -540,7 +540,7 @@ dictionary * iniparser_load(const char * ininame)
             len-- ;
         }
         /* Detect multi-line */
-        if (line[len]=='\\') {
+        if (len >= 0 && line[len]=='\\') {
             /* Multi-line value */
             last=len ;
             continue ;
-- 
2.30.2