From 70cca8228435e9cbd88c012f22b9c917a39b1535 Mon Sep 17 00:00:00 2001 From: Bhupesh Sharma Date: Wed, 23 Sep 2020 16:42:37 +0530 Subject: kexec: Fix snprintf related compilation warnings MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit This patch fixes the following snprintf related compilation warning seen currently with gcc versions 7 and 8 when kexec is compiled with -Wformat-truncation option: kexec/fs2dt.c:673:34: warning: ‘stdout-path’ directive output may be truncated writing 11 bytes into a region of size between 1 and 1024 [-Wformat-truncation=] snprintf(filename, MAXPATH, "%sstdout-path", pathname); ^~~~~~~~~~~ kexec/fs2dt.c:673:3: note: ‘snprintf’ output between 12 and 1035 bytes into a destination of size 1024 snprintf(filename, MAXPATH, "%sstdout-path", pathname); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kexec/fs2dt.c:676:35: warning: ‘linux,stdout-path’ directive output may be truncated writing 17 bytes into a region of size between 1 and 1024 [-Wformat-truncation=] snprintf(filename, MAXPATH, "%slinux,stdout-path", pathname); ^~~~~~~~~~~~~~~~~ kexec/fs2dt.c:676:4: note: ‘snprintf’ output between 18 and 1041 bytes into a destination of size 1024 snprintf(filename, MAXPATH, "%slinux,stdout-path", pathname); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kexec/firmware_memmap.c:132:35: warning: ‘%s’ directive output may be truncated writing 5 bytes into a region of size between 0 and 4095 [-Wformat-truncation=] snprintf(filename, PATH_MAX, "%s/%s", entry, "start"); ^~ ~~~~~~~ kexec/firmware_memmap.c:132:2: note: ‘snprintf’ output between 7 and 4102 bytes into a destination of size 4096 snprintf(filename, PATH_MAX, "%s/%s", entry, "start"); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kexec/firmware_memmap.c:142:35: warning: ‘%s’ directive output may be truncated writing 3 bytes into a region of size between 0 and 4095 [-Wformat-truncation=] snprintf(filename, PATH_MAX, "%s/%s", entry, "end"); ^~ ~~~~~ kexec/firmware_memmap.c:142:2: note: ‘snprintf’ output between 5 and 4100 bytes into a destination of size 4096 snprintf(filename, PATH_MAX, "%s/%s", entry, "end"); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ kexec/firmware_memmap.c:152:35: warning: ‘%s’ directive output may be truncated writing 4 bytes into a region of size between 0 and 4095 [-Wformat-truncation=] snprintf(filename, PATH_MAX, "%s/%s", entry, "type"); ^~ ~~~~~~ kexec/firmware_memmap.c:152:2: note: ‘snprintf’ output between 6 and 4101 bytes into a destination of size 4096 snprintf(filename, PATH_MAX, "%s/%s", entry, "type"); ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ Since the simplest method to address the gcc warnings and possible truncation would be to check the return value provided from snprintf (well there are other methods like using 'asnprintf' or using 'open_memstream' function to create the FILE object, but these are more intrusive), so this patch does the same. Cc: Simon Horman Cc: Eric Biederman Cc: kexec@lists.infradead.org Signed-off-by: Bhupesh Sharma Signed-off-by: Simon Horman --- kexec/firmware_memmap.c | 22 +++++++++++++++++++--- kexec/fs2dt.c | 16 +++++++++++++--- 2 files changed, 32 insertions(+), 6 deletions(-) diff --git a/kexec/firmware_memmap.c b/kexec/firmware_memmap.c index 1ee214aa..457c3dc9 100644 --- a/kexec/firmware_memmap.c +++ b/kexec/firmware_memmap.c @@ -125,11 +125,17 @@ static int parse_memmap_entry(const char *entry, struct memory_range *range) { char filename[PATH_MAX]; char *type; + int ret; /* * entry/start */ - snprintf(filename, PATH_MAX, "%s/%s", entry, "start"); + ret = snprintf(filename, PATH_MAX, "%s/%s", entry, "start"); + if (ret < 0 || ret >= PATH_MAX) { + fprintf(stderr, "snprintf failed: %s\n", strerror(errno)); + return -1; + } + filename[PATH_MAX-1] = 0; range->start = parse_numeric_sysfs(filename); @@ -139,7 +145,12 @@ static int parse_memmap_entry(const char *entry, struct memory_range *range) /* * entry/end */ - snprintf(filename, PATH_MAX, "%s/%s", entry, "end"); + ret = snprintf(filename, PATH_MAX, "%s/%s", entry, "end"); + if (ret < 0 || ret >= PATH_MAX) { + fprintf(stderr, "snprintf failed: %s\n", strerror(errno)); + return -1; + } + filename[PATH_MAX-1] = 0; range->end = parse_numeric_sysfs(filename); @@ -149,7 +160,12 @@ static int parse_memmap_entry(const char *entry, struct memory_range *range) /* * entry/type */ - snprintf(filename, PATH_MAX, "%s/%s", entry, "type"); + ret = snprintf(filename, PATH_MAX, "%s/%s", entry, "type"); + if (ret < 0 || ret >= PATH_MAX) { + fprintf(stderr, "snprintf failed: %s\n", strerror(errno)); + return -1; + } + filename[PATH_MAX-1] = 0; type = parse_string_sysfs(filename); diff --git a/kexec/fs2dt.c b/kexec/fs2dt.c index 07a5e2f9..1a43058b 100644 --- a/kexec/fs2dt.c +++ b/kexec/fs2dt.c @@ -568,7 +568,7 @@ static void putnode(void) struct dirent **namelist; int numlist, i; struct stat statbuf; - int plen; + int plen, ret; numlist = scandir(pathname, &namelist, 0, comparefunc); if (numlist < 0) @@ -670,10 +670,20 @@ static void putnode(void) * code can print 'I'm in purgatory' message. Currently only * pseries/hvcterminal is supported. */ - snprintf(filename, MAXPATH, "%sstdout-path", pathname); + ret = snprintf(filename, MAXPATH, "%sstdout-path", pathname); + if (ret < 0 || ret >= MAXPATH) { + fprintf(stderr, "snprintf failed: %s\n", strerror(errno)); + goto no_debug; + } + fd = open(filename, O_RDONLY); if (fd == -1) { - snprintf(filename, MAXPATH, "%slinux,stdout-path", pathname); + ret = snprintf(filename, MAXPATH, "%slinux,stdout-path", pathname); + if (ret < 0 || ret >= MAXPATH) { + fprintf(stderr, "snprintf failed: %s\n", strerror(errno)); + goto no_debug; + } + fd = open(filename, O_RDONLY); if (fd == -1) { printf("Unable to find %s[linux,]stdout-path, printing from purgatory is disabled\n", -- cgit 1.2.3-korg