[PATCH v8 12/18] eal: check for hugefile path overflow

Stephen Hemminger
2025-12-28T20:20:40Z

When constructing huge filename path, check for possible
overflow of PATH_MAX.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
lib/eal/common/eal_filesystem.h | 10 ++++---
lib/eal/linux/eal_hugepage_info.c | 44 ++++++++++++++++++-------------
lib/eal/linux/eal_memalloc.c | 11 ++++++--
lib/eal/linux/eal_memory.c | 9 +++++--
4 files changed, 48 insertions(+), 26 deletions(-)

diff --git a/lib/eal/common/eal_filesystem.h b/lib/eal/common/eal_filesystem.h
index 2de88d7cc2..90b1cbb484 100644
--- a/lib/eal/common/eal_filesystem.h
+++ b/lib/eal/common/eal_filesystem.h
@@ -100,12 +100,14 @@ eal_hugepage_data_path(void)

/** String format for hugepage map files. */
#define HUGEFILE_FMT "%s/%smap_%d"
-static inline const char *
+static inline __rte_warn_unused_result const char *
eal_get_hugefile_path(char *buffer, size_t buflen, const char *hugedir, int f_id)
{
- snprintf(buffer, buflen, HUGEFILE_FMT, hugedir,
- eal_get_hugefile_prefix(), f_id);
- return buffer;
+ if (snprintf(buffer, buflen, HUGEFILE_FMT, hugedir,
+ eal_get_hugefile_prefix(), f_id) >= (int)buflen)
+ return NULL;
+ else
+ return buffer;
}

/** define the default filename prefix for the %s values above */
diff --git a/lib/eal/linux/eal_hugepage_info.c b/lib/eal/linux/eal_hugepage_info.c
index fe3351259e..cddffb9efb 100644
--- a/lib/eal/linux/eal_hugepage_info.c
+++ b/lib/eal/linux/eal_hugepage_info.c
@@ -68,11 +68,14 @@ create_shared_memory(const char *filename, const size_t mem_size)

static int get_hp_sysfs_value(const char *subdir, const char *file, unsigned long *val)
{
- char path[PATH_MAX];
+ char *path = NULL;
+ int ret;

- snprintf(path, sizeof(path), "%s/%s/%s",
- sys_dir_path, subdir, file);
- return eal_parse_sysfs_value(path, val);
+ if (asprintf(&path, "%s/%s/%s", sys_dir_path, subdir, file) < 0)
+ return -1;
+ ret = eal_parse_sysfs_value(path, val);
+ free(path);
+ return ret;
}

/* this function is only called from eal_hugepage_info_init which itself
@@ -133,13 +136,15 @@ get_num_hugepages(const char *subdir, size_t sz, unsigned int reusable_pages)
static uint32_t
get_num_hugepages_on_node(const char *subdir, unsigned int socket, size_t sz)
{
- char path[PATH_MAX], socketpath[PATH_MAX];
+ char *path = NULL, *socketpath = NULL;
DIR *socketdir;
unsigned long num_pages = 0;
const char *nr_hp_file = "free_hugepages";

- snprintf(socketpath, sizeof(socketpath), "%s/node%u/hugepages",
- sys_pages_numa_dir_path, socket);
+ if (asprintf(&socketpath, "%s/node%u/hugepages", sys_pages_numa_dir_path, socket) < 0) {
+ EAL_LOG(ERR, "Can not format node huge page path");
+ goto nopages;
+ }

socketdir = opendir(socketpath);
if (socketdir) {
@@ -147,17 +152,16 @@ get_num_hugepages_on_node(const char *subdir, unsigned int socket, size_t sz)
closedir(socketdir);
} else {
/* Can't find socket dir, so ignore it */
- return 0;
+ goto nopages;
}

- if (snprintf(path, sizeof(path), "%s/%s/%s", socketpath, subdir, nr_hp_file) >= PATH_MAX) {
- EAL_LOG(NOTICE, "Socket path %s/%s/%s is truncated",
- socketpath, subdir, nr_hp_file);
- return 0;
+ if (asprintf(&path, "%s/%s/%s", socketpath, subdir, nr_hp_file) < 0) {
+ EAL_LOG(ERR, "Can not format free hugepages path");
+ goto nopages;
}

if (eal_parse_sysfs_value(path, &num_pages) < 0)
- return 0;
+ goto nopages;

if (num_pages == 0)
EAL_LOG(WARNING, "No free %zu kB hugepages reported on node %u",
@@ -170,6 +174,10 @@ get_num_hugepages_on_node(const char *subdir, unsigned int socket, size_t sz)
if (num_pages > UINT32_MAX)
num_pages = UINT32_MAX;

+nopages:
+ free(path);
+ free(socketpath);
+
return num_pages;
}

@@ -204,7 +212,7 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
const char proc_mounts[] = "/proc/mounts";
const char pagesize_opt[] = "pagesize=";
const size_t pagesize_opt_len = sizeof(pagesize_opt) - 1;
- char found[PATH_MAX] = "";
+ const char *found = NULL;
char buf[BUFSIZ];
struct mntent entry;
const struct internal_config *internal_conf =
@@ -247,7 +255,7 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
* If no --huge-dir option has been given, we're done.
*/
if (internal_conf->hugepage_dir == NULL) {
- strlcpy(found, entry.mnt_dir, len);
+ found = entry.mnt_dir;
break;
}

@@ -267,13 +275,13 @@ get_hugepage_dir(uint64_t hugepage_sz, char *hugedir, int len)
* We found a match, but only prefer it if it's a longer match
* (so /mnt/1 is preferred over /mnt for matching /mnt/1/2)).
*/
- if (mountpt_len > strlen(found))
- strlcpy(found, entry.mnt_dir, len);
+ if (found == NULL || mountpt_len > strlen(found))
+ found = strdupa(entry.mnt_dir);
} /* end while fgets */

endmntent(mounts);

- if (found[0] != '\0') {
+ if (found != NULL) {
/* If needed, return the requested dir, not the mount point. */
strlcpy(hugedir, internal_conf->hugepage_dir != NULL ?
internal_conf->hugepage_dir : found, len);
diff --git a/lib/eal/linux/eal_memalloc.c b/lib/eal/linux/eal_memalloc.c
index 1e60e21620..d9e8ea76b9 100644
--- a/lib/eal/linux/eal_memalloc.c
+++ b/lib/eal/linux/eal_memalloc.c
@@ -260,6 +260,7 @@ get_seg_fd(char *path, int buflen, struct hugepage_info *hi,
{
int fd;
int *out_fd;
+ const char *huge_path;
struct stat st;
int ret;
const struct internal_config *internal_conf =
@@ -276,12 +277,18 @@ get_seg_fd(char *path, int buflen, struct hugepage_info *hi,

if (internal_conf->single_file_segments) {
out_fd = &fd_list[list_idx].memseg_list_fd;
- eal_get_hugefile_path(path, buflen, hi->hugedir, list_idx);
+ huge_path = eal_get_hugefile_path(path, buflen, hi->hugedir, list_idx);
} else {
out_fd = &fd_list[list_idx].fds[seg_idx];
- eal_get_hugefile_path(path, buflen, hi->hugedir,
+ huge_path = eal_get_hugefile_path(path, buflen, hi->hugedir,
list_idx * RTE_MAX_MEMSEG_PER_LIST + seg_idx);
}
+ if (huge_path == NULL) {
+ EAL_LOG(DEBUG, "%s(): hugefile path truncated: '%s'",
+ __func__, path);
+ return -1;
+ }
+
fd = *out_fd;
if (fd >= 0)
return fd;
diff --git a/lib/eal/linux/eal_memory.c b/lib/eal/linux/eal_memory.c
index 8e1763e890..2a0a441398 100644
--- a/lib/eal/linux/eal_memory.c
+++ b/lib/eal/linux/eal_memory.c
@@ -337,8 +337,13 @@ map_all_hugepages(struct hugepage_file *hugepg_tbl, struct hugepage_info *hpi,

hf->file_id = i;
hf->size = hugepage_sz;
- eal_get_hugefile_path(hf->filepath, sizeof(hf->filepath),
- hpi->hugedir, hf->file_id);
+ if (eal_get_hugefile_path(hf->filepath, sizeof(hf->filepath),
+ hpi->hugedir, hf->file_id) == NULL) {
+ EAL_LOG(DEBUG, "%s(): huge file path '%s' truncated",
+ __func__, hf->filepath);
+ goto out;
+ }
+
hf->filepath[sizeof(hf->filepath) - 1] = '\0';

/* try to create hugepage file */
--
2.51.0