From 8e0ad48c21bd7d5506ff44eb4c04f796b80045ce Mon Sep 17 00:00:00 2001 From: Samanta Navarro Date: Mon, 30 Jan 2023 11:54:49 +0000 Subject: [PATCH] Prevent out of boundary access If lines start with '\0' then it is possible to trigger out of boundary accesses. Check if indices are valid before accessing them. Signed-off-by: Samanta Navarro --- src/login_nopam.c | 4 ++-- src/suauth.c | 3 ++- 2 files changed, 4 insertions(+), 3 deletions(-) diff --git a/src/login_nopam.c b/src/login_nopam.c index b09cffe4..18072a43 100644 --- a/src/login_nopam.c +++ b/src/login_nopam.c @@ -100,7 +100,7 @@ int login_access (const char *user, const char *from) int end; lineno++; end = (int) strlen (line) - 1; - if (line[end] != '\n') { + if (line[0] == '\0' || line[end] != '\n') { SYSLOG ((LOG_ERR, "%s: line %d: missing newline or line too long", TABLE, lineno)); @@ -320,7 +320,7 @@ static bool from_match (const char *tok, const char *string) if (strchr (string, '.') == NULL) { return true; } - } else if ( (tok[(tok_len = strlen (tok)) - 1] == '.') /* network */ + } else if ( (tok[0] != '\0' && tok[(tok_len = strlen (tok)) - 1] == '.') /* network */ && (strncmp (tok, resolve_hostname (string), tok_len) == 0)) { return true; } diff --git a/src/suauth.c b/src/suauth.c index 2641d334..d68a3340 100644 --- a/src/suauth.c +++ b/src/suauth.c @@ -68,8 +68,9 @@ int check_su_auth (const char *actual_id, while (fgets (temp, sizeof (temp), authfile_fd) != NULL) { lines++; + endline = strlen(temp) - 1; - if (temp[endline = strlen (temp) - 1] != '\n') { + if (temp[0] == '\0' || temp[endline] != '\n') { SYSLOG ((LOG_ERR, "%s, line %d: line too long or missing newline", SUAUTHFILE, lines));