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    Subject[PATCH 5.19 1024/1157] tools/thermal: Fix possible path truncations
    Date
    From: Florian Fainelli <f.fainelli@gmail.com>

    [ Upstream commit 6c58cf40e3a1d2f47c09d3489857e9476316788a ]

    A build with -D_FORTIFY_SOURCE=2 enabled will produce the following warnings:

    sysfs.c:63:30: warning: '%s' directive output may be truncated writing up to 255 bytes into a region of size between 0 and 255 [-Wformat-truncation=]
    snprintf(filepath, 256, "%s/%s", path, filename);
    ^~
    Bump up the buffer to PATH_MAX which is the limit and account for all of
    the possible NUL and separators that could lead to exceeding the
    allocated buffer sizes.

    Fixes: 94f69966faf8 ("tools/thermal: Introduce tmon, a tool for thermal subsystem")
    Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>
    Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
    Signed-off-by: Sasha Levin <sashal@kernel.org>
    ---
    tools/thermal/tmon/sysfs.c | 24 +++++++++++++-----------
    1 file changed, 13 insertions(+), 11 deletions(-)

    diff --git a/tools/thermal/tmon/sysfs.c b/tools/thermal/tmon/sysfs.c
    index b00b1bfd9d8e..cb1108bc9249 100644
    --- a/tools/thermal/tmon/sysfs.c
    +++ b/tools/thermal/tmon/sysfs.c
    @@ -13,6 +13,7 @@
    #include <stdint.h>
    #include <dirent.h>
    #include <libintl.h>
    +#include <limits.h>
    #include <ctype.h>
    #include <time.h>
    #include <syslog.h>
    @@ -33,9 +34,9 @@ int sysfs_set_ulong(char *path, char *filename, unsigned long val)
    {
    FILE *fd;
    int ret = -1;
    - char filepath[256];
    + char filepath[PATH_MAX + 2]; /* NUL and '/' */

    - snprintf(filepath, 256, "%s/%s", path, filename);
    + snprintf(filepath, sizeof(filepath), "%s/%s", path, filename);

    fd = fopen(filepath, "w");
    if (!fd) {
    @@ -57,9 +58,9 @@ static int sysfs_get_ulong(char *path, char *filename, unsigned long *p_ulong)
    {
    FILE *fd;
    int ret = -1;
    - char filepath[256];
    + char filepath[PATH_MAX + 2]; /* NUL and '/' */

    - snprintf(filepath, 256, "%s/%s", path, filename);
    + snprintf(filepath, sizeof(filepath), "%s/%s", path, filename);

    fd = fopen(filepath, "r");
    if (!fd) {
    @@ -76,9 +77,9 @@ static int sysfs_get_string(char *path, char *filename, char *str)
    {
    FILE *fd;
    int ret = -1;
    - char filepath[256];
    + char filepath[PATH_MAX + 2]; /* NUL and '/' */

    - snprintf(filepath, 256, "%s/%s", path, filename);
    + snprintf(filepath, sizeof(filepath), "%s/%s", path, filename);

    fd = fopen(filepath, "r");
    if (!fd) {
    @@ -199,8 +200,8 @@ static int find_tzone_cdev(struct dirent *nl, char *tz_name,
    {
    unsigned long trip_instance = 0;
    char cdev_name_linked[256];
    - char cdev_name[256];
    - char cdev_trip_name[256];
    + char cdev_name[PATH_MAX];
    + char cdev_trip_name[PATH_MAX];
    int cdev_id;

    if (nl->d_type == DT_LNK) {
    @@ -213,7 +214,8 @@ static int find_tzone_cdev(struct dirent *nl, char *tz_name,
    return -EINVAL;
    }
    /* find the link to real cooling device record binding */
    - snprintf(cdev_name, 256, "%s/%s", tz_name, nl->d_name);
    + snprintf(cdev_name, sizeof(cdev_name) - 2, "%s/%s",
    + tz_name, nl->d_name);
    memset(cdev_name_linked, 0, sizeof(cdev_name_linked));
    if (readlink(cdev_name, cdev_name_linked,
    sizeof(cdev_name_linked) - 1) != -1) {
    @@ -226,8 +228,8 @@ static int find_tzone_cdev(struct dirent *nl, char *tz_name,
    /* find the trip point in which the cdev is binded to
    * in this tzone
    */
    - snprintf(cdev_trip_name, 256, "%s%s", nl->d_name,
    - "_trip_point");
    + snprintf(cdev_trip_name, sizeof(cdev_trip_name) - 1,
    + "%s%s", nl->d_name, "_trip_point");
    sysfs_get_ulong(tz_name, cdev_trip_name,
    &trip_instance);
    /* validate trip point range, e.g. trip could return -1
    --
    2.35.1


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