[RFC v2 13/14] eal: check for hugefile path overflow

Stephen Hemminger
2025-12-05T02:31:13Z

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_memalloc.c | 11 +++++++++--
lib/eal/linux/eal_memory.c | 9 +++++++--
3 files changed, 22 insertions(+), 8 deletions(-)

diff --git a/lib/eal/common/eal_filesystem.h b/lib/eal/common/eal_filesystem.h
index 5371d9f1d6..006d2ff3e5 100644
--- a/lib/eal/common/eal_filesystem.h
+++ b/lib/eal/common/eal_filesystem.h
@@ -93,12 +93,14 @@ 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_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