From a3708cf6b0a5a68e2ed1ce3db28a03ed21d368d2 Mon Sep 17 00:00:00 2001 From: Joseph Myers Date: Mon, 19 Dec 2022 14:45:44 +0000 Subject: [PATCH] Avoid use of atoi in some places in libc This patch is split out of . atoi has undefined behavior on out-of-range input, which makes it problematic to use anywhere in glibc that might be processing input out-of-range for atoi but not specified to produce undefined behavior for the function calling atoi. Change some uses of atoi to call strtol instead; this avoids the undefined behavior, though there is no guarantee that the overflow handling of strtol is really right in those places either. This also serves to avoid localplt test failures given an installed header redirection for strtol (which means that the call from the inline atoi implementation doesn't end up at a hidden alias from libc_hidden_proto). Certainly, the use of atoi is questionable in argp-help.c (shared with gnulib, so shouldn't depend on glibc implementation details, and processing user-provided input), and maybe also in argp-parse.c (I'm not sure what that code in argp-parse.c is meant to be used for). I also changed inet/rexec.c and resolv/res_init.c similarly to use strtol to avoid such localplt failures, although given those files (in those versions) are only used in glibc it's not problematic for them to rely on the specific behavior of glibc's atoi on out-of-range input (in the absence of compiler optimizations based on the undefined behavior) in the same way it's problematic for gnulib code to do so. There may be other uses of atoi (or atol or atoll), in any of glibc's installed code, for which it would also be appropriate to avoid the undefined behavior on out-of-range input; this patch only fixes the specific cases needed to avoid localplt failures. Tested for x86_64. --- argp/argp-help.c | 6 +++--- argp/argp-parse.c | 2 +- inet/rexec.c | 2 +- resolv/res_init.c | 6 +++--- 4 files changed, 8 insertions(+), 8 deletions(-) diff --git a/argp/argp-help.c b/argp/argp-help.c index 90a2795..f7f1134c 100644 --- a/argp/argp-help.c +++ b/argp/argp-help.c @@ -210,9 +210,9 @@ fill_in_uparams (const struct argp_state *state) } else if (isdigit ((unsigned char) *arg)) { - val = atoi (arg); - while (isdigit ((unsigned char) *arg)) - arg++; + char *ep; + val = strtol (arg, &ep, 10); + arg = ep; SKIPWS (arg); } diff --git a/argp/argp-parse.c b/argp/argp-parse.c index 68dc454..1533b43 100644 --- a/argp/argp-parse.c +++ b/argp/argp-parse.c @@ -147,7 +147,7 @@ argp_default_parser (int key, char *arg, struct argp_state *state) break; case OPT_HANG: - _argp_hang = atoi (arg ? arg : "3600"); + _argp_hang = arg ? strtol (arg, NULL, 10) : 3600; while (_argp_hang-- > 0) __sleep (1); break; diff --git a/inet/rexec.c b/inet/rexec.c index 064e979..c647b7a 100644 --- a/inet/rexec.c +++ b/inet/rexec.c @@ -134,7 +134,7 @@ retry: if (!getnameinfo(&sa2.sa, sa2len, NULL, 0, servbuff, sizeof(servbuff), NI_NUMERICSERV)) - port = atoi(servbuff); + port = strtol(servbuff, NULL, 10); (void) sprintf(num, "%u", port); (void) __write(s, num, strlen(num)+1); { socklen_t len = sizeof (from); diff --git a/resolv/res_init.c b/resolv/res_init.c index 2c0bea6..61b958a 100644 --- a/resolv/res_init.c +++ b/resolv/res_init.c @@ -654,7 +654,7 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options) /* Search for and process individual options. */ if (!strncmp (cp, "ndots:", sizeof ("ndots:") - 1)) { - int i = atoi (cp + sizeof ("ndots:") - 1); + int i = strtol (cp + sizeof ("ndots:") - 1, NULL, 10); if (i <= RES_MAXNDOTS) parser->template.ndots = i; else @@ -662,7 +662,7 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options) } else if (!strncmp (cp, "timeout:", sizeof ("timeout:") - 1)) { - int i = atoi (cp + sizeof ("timeout:") - 1); + int i = strtol (cp + sizeof ("timeout:") - 1, NULL, 10); if (i <= RES_MAXRETRANS) parser->template.retrans = i; else @@ -670,7 +670,7 @@ res_setoptions (struct resolv_conf_parser *parser, const char *options) } else if (!strncmp (cp, "attempts:", sizeof ("attempts:") - 1)) { - int i = atoi (cp + sizeof ("attempts:") - 1); + int i = strtol (cp + sizeof ("attempts:") - 1, NULL, 10); if (i <= RES_MAXRETRY) parser->template.retry = i; else -- 2.7.4