From a2bd2a8ea5ef687e8b4dc2694f7d5e99a1ec2a06 Mon Sep 17 00:00:00 2001 From: Nicolas Iooss Date: Thu, 12 Nov 2020 21:24:06 +0100 Subject: [PATCH] libsepol: free memory when realloc() fails In get_class_info(), if realloc(class_buf, new_class_buf_len) fails to grow the memory, the function returns NULL without freeing class_buf. This leads to a memory leak which is reported by clang's static analyzer: https://580-118970575-gh.circle-artifacts.com/0/output-scan-build/2020-11-11-194150-6152-1/report-42a899.html#EndPath Fix the memory leak by calling free(class_buf). While at it, use size_t insted of int to store the size of the buffer which is growing. Signed-off-by: Nicolas Iooss --- libsepol/src/services.c | 19 +++++++++++-------- 1 file changed, 11 insertions(+), 8 deletions(-) diff --git a/libsepol/src/services.c b/libsepol/src/services.c index beb0711f6680..72b39657cd2e 100644 --- a/libsepol/src/services.c +++ b/libsepol/src/services.c @@ -312,17 +312,20 @@ static char *get_class_info(sepol_security_class_t tclass, else state_num = mls + 2; - int class_buf_len = 0; - int new_class_buf_len; - int len, buf_used; + size_t class_buf_len = 0; + size_t new_class_buf_len; + size_t buf_used; + int len; char *class_buf = NULL, *p; char *new_class_buf = NULL; while (1) { new_class_buf_len = class_buf_len + EXPR_BUF_SIZE; new_class_buf = realloc(class_buf, new_class_buf_len); - if (!new_class_buf) - return NULL; + if (!new_class_buf) { + free(class_buf); + return NULL; + } class_buf_len = new_class_buf_len; class_buf = new_class_buf; buf_used = 0; @@ -330,7 +333,7 @@ static char *get_class_info(sepol_security_class_t tclass, /* Add statement type */ len = snprintf(p, class_buf_len - buf_used, "%s", statements[state_num]); - if (len < 0 || len >= class_buf_len - buf_used) + if (len < 0 || (size_t)len >= class_buf_len - buf_used) continue; /* Add class entry */ @@ -338,7 +341,7 @@ static char *get_class_info(sepol_security_class_t tclass, buf_used += len; len = snprintf(p, class_buf_len - buf_used, "%s ", policydb->p_class_val_to_name[tclass - 1]); - if (len < 0 || len >= class_buf_len - buf_used) + if (len < 0 || (size_t)len >= class_buf_len - buf_used) continue; /* Add permission entries (validatetrans does not have perms) */ @@ -351,7 +354,7 @@ static char *get_class_info(sepol_security_class_t tclass, } else { len = snprintf(p, class_buf_len - buf_used, "("); } - if (len < 0 || len >= class_buf_len - buf_used) + if (len < 0 || (size_t)len >= class_buf_len - buf_used) continue; break; } -- 2.29.2