Hi Michael,
Thank you so much for a review!

I'll add the failure checks in the code mentioned by you.

On build issue. I haven't observed any of these errors on my machine. Today, I built the latest upstream grub with this patch on my machine and no errors are observed.

Regards,
Avnish Chouhan

On 2025-02-12 13:44, Michael Chang wrote:
Hi Avnish,

This patch doesn't build:

  ../grub-core/osdep/linux/ofpath.c: In function ‘of_path_of_nvme’:
  ../grub-core/osdep/linux/ofpath.c:729:37: error: ‘%x’ directive
output may be truncated writing between 1 and 8 bytes into a region of
size 7 [-Werror=format-truncation=]
    729 |                         "/namespace@%x:%d", nsid, part);
        |                                     ^~
  ../grub-core/osdep/linux/ofpath.c:729:25: note: directive argument
in the range [1, 4294967295]
    729 |                         "/namespace@%x:%d", nsid, part);
        |                         ^~~~~~~~~~~~~~~~~~
  ../grub-core/osdep/linux/ofpath.c:728:15: note: ‘snprintf’ output
between 15 and 32 bytes into a destination of size 18
    728 |               snprintf (disk+chars_written,
sizeof("/namespace@") + MAX_NVME_NSID_DIGITS,
        |
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    729 |                         "/namespace@%x:%d", nsid, part);
        |                         ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
  ../grub-core/osdep/linux/ofpath.c:770:37: error: ‘%x’ directive
output may be truncated writing between 1 and 8 bytes into a region of
size 7 [-Werror=format-truncation=]
    770 |                         "/namespace@%x", nsid);
        |                                     ^~
  ../grub-core/osdep/linux/ofpath.c:770:25: note: directive argument
in the range [1, 4294967295]
    770 |                         "/namespace@%x", nsid);
        |                         ^~~~~~~~~~~~~~~
  ../grub-core/osdep/linux/ofpath.c:769:15: note: ‘snprintf’ output
between 13 and 20 bytes into a destination of size 18
    769 |               snprintf
(disk+chars_written,sizeof("/namespace@") + sizeof(char) *
MAX_NVME_NSID_DIGITS,
        |
^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
    770 |                         "/namespace@%x", nsid);
        |                         ~~~~~~~~~~~~~~~~~~~~~~
  cc1: all warnings being treated as errors

The error is valid. It is pointing to that the size,
MAX_NVME_NSID_DIGITS, provided for snprintf() is too small to the worse
case of format specifier output, thus the result truncated.

The `gcc --version`:
  gcc (SUSE Linux) 14.2.1 20241007 [revision
4af44f2cf7d281f3e4f3957efce10e8b2ccb2ad3]

Moreover, it has a few critical memory related issue that may crash the
program. (See below)

On Fri, Aug 30, 2024 at 05:11:04PM +0530, Avnish Chouhan wrote:
This patch adds code to enable the translation of logical devices to the of NVMeoFC paths.

Signed-off-by: Diego Domingos <dieg...@br.ibm.com>
Signed-off-by: Avnish Chouhan <avn...@linux.ibm.com>
---
grub-core/osdep/linux/ofpath.c | 371 +++++++++++++++++++++++++++++++++++++++++++++++++++++--
 include/grub/util/ofpath.h     | 28 ++++++++++++++++++++++++++++
 2 files changed, 390 insertions(+), 9 deletions(-)

diff --git a/grub-core/osdep/linux/ofpath.c b/grub-core/osdep/linux/ofpath.c
index 0f5d54e..f0e7dcc 100644
--- a/grub-core/osdep/linux/ofpath.c
+++ b/grub-core/osdep/linux/ofpath.c
@@ -37,6 +37,7 @@
 #include <fcntl.h>
 #include <errno.h>
 #include <ctype.h>
+#include <dirent.h>

 #ifdef __sparc__
 typedef enum
@@ -136,7 +137,7 @@ trim_newline (char *path)
     *end-- = '\0';
 }

-#define MAX_DISK_CAT    64
+#define MAX_DISK_CAT    512

 static char *
 find_obppath (const char *sysfs_path_orig)
@@ -312,6 +313,91 @@ get_basename(char *p)
   return ret;
 }

+int
+add_filename_to_pile (char *filename, struct ofpath_files_list_root* root)
+{
+  struct ofpath_files_list_node* file;
+
+  file = malloc (sizeof (struct ofpath_files_list_node));
+  if (!file)
+    return -1;
+
+  file->filename = malloc (sizeof (char) * 1024);
+  if (!file->filename)
+    {
+      free (file);
+      return -1;
+    }
+
+  grub_strcpy (file->filename, filename);
+  if (root->first == NULL)
+    {
+      root->items = 1;
+      root->first = file;
+      file->next = NULL;
+    }
+  else
+    {
+      root->items++;
+      file->next = root->first;
+      root->first = file;
+    }
+
+  return 0;
+}
+
+void
+find_file (char* filename, char* directory, struct ofpath_files_list_root* root, int max_depth, int depth)
+{
+  struct dirent *ep;
+  struct stat statbuf;
+  DIR *dp;
+  int ret_val=0;
+  char* full_path;
+
+  if (depth > max_depth)
+    {
+      return;
+    }
+
+  if ((dp = opendir (directory)) == NULL)
+    {
+      return;
+    }
+
+  full_path = malloc (1024 * sizeof (char));
+  if (!full_path)
+    return;
+
+  while ((ep = readdir(dp)) != NULL)
+    {
+      snprintf (full_path, 1024, "%s/%s", directory, ep->d_name);
+      lstat (full_path, &statbuf);
+
+      if (S_ISLNK (statbuf.st_mode))
+        {
+          continue;
+        }
+
+      if (!strcmp (ep->d_name, ".") || !strcmp(ep->d_name, ".."))
+        {
+          continue;
+        }
+
+      if (!strcmp (ep->d_name, filename))
+        {
+          ret_val = add_filename_to_pile (full_path, root);
+          if (ret_val == -1)
+            continue;
+        }
+
+      find_file (filename, full_path, root, max_depth, depth+1);
+    }
+
+  free (full_path);
+  closedir (dp);
+}
+
 static char *
 of_path_of_vdisk(const char *sys_devname __attribute__((unused)),
                 const char *device,
@@ -382,7 +468,200 @@ of_fc_port_name (const char *path, const char *subpath, char *port_name)
   free (basepath);
 }

-#ifdef __sparc__
+void
+free_ofpath_files_list (struct ofpath_files_list_root* root)
+{
+  struct ofpath_files_list_node* node = root->first;
+  struct ofpath_files_list_node* next;
+
+  while (node!=NULL)
+    {
+      next = node->next;
+      free (node->filename);
+      free (node);
+      node = next;
+    }
+
+  free (root);
+  return;
+}
+
+char*
+of_find_fc_host (char* host_wwpn)
+{
+  FILE* fp;
+  char *buf;
+  char *ret_val;
+  char portname_filename[sizeof ("port_name")] = "port_name";
+  char devices_path[sizeof ("/sys/devices")] = "/sys/devices";
+  struct ofpath_files_list_root* portnames_file_list;
+  struct ofpath_files_list_node* node;
+
+  ret_val = malloc (sizeof (char) * 1024);
+  if (!ret_val)
+    return NULL;
+
+ portnames_file_list = malloc (sizeof (struct ofpath_files_list_root));
+  if (!portnames_file_list)
+    {
+      free (ret_val);
+      return NULL;
+    }
+
+  portnames_file_list->items = 0;
+  portnames_file_list->first = NULL;
+ find_file (portname_filename, devices_path, portnames_file_list, 10, 0);
+  node = portnames_file_list->first;
+
+  while (node != NULL)
+    {
+      fp = fopen(node->filename, "r");
+      buf = malloc (sizeof (char) * 512);
+      if (!buf)
+        break;
+
+      fscanf (fp, "%s", buf);
+      fclose (fp);
+
+ if ((strcmp (buf, host_wwpn) == 0) && grub_strstr (node->filename, "fc_host"))
+        {
+          free (buf);
+          grub_strcpy (ret_val, node->filename);
+          free_ofpath_files_list (portnames_file_list);
+          return ret_val;
+        }
+
+      node = node->next;
+      free (buf);
+    }
+  free_ofpath_files_list (portnames_file_list);
+  free (ret_val);
+  return NULL;
+}
+
+int
+of_path_get_nvmeof_adapter_info (char* sysfs_path,
+ struct ofpath_nvmeof_info* nvmeof_info)
+{
+  FILE *fp;
+  char *buf, *buf2, *buf3;
+
+  nvmeof_info->host_wwpn = malloc (sizeof (char) * 256);
+  nvmeof_info->target_wwpn = malloc (sizeof (char) * 256);
+  nvmeof_info->nqn = malloc (sizeof (char) * 256);
+
+ if (nvmeof_info->host_wwpn == NULL || nvmeof_info->target_wwpn == NULL || nvmeof_info->nqn == NULL)
+    {
+      free (nvmeof_info->host_wwpn);
+      free (nvmeof_info->target_wwpn);
+      free (nvmeof_info->nqn);
+      return -1;
+    }
+
+  buf = malloc (sizeof (char) * 512);
+  if (!buf)
+    {
+      free (nvmeof_info->host_wwpn);
+      free (nvmeof_info->target_wwpn);
+      free (nvmeof_info->nqn);
+      return -1;
+    }
+
+  snprintf (buf, 512, "%s/subsysnqn", sysfs_path);
+  fp = fopen (buf, "r");

The fp == NULL check is missing.

+  fscanf (fp, "%s", nvmeof_info->nqn);

The return value of fscanf() should be checked to verify that the nqn
read from the file is successful.

+  fclose (fp);
+
+  snprintf (buf, 512, "%s/cntlid", sysfs_path);
+  fp = fopen (buf, "r");

Ditto.

+  fscanf (fp, "%u", &(nvmeof_info->cntlid));

Ditto.

+  fclose (fp);
+
+  snprintf (buf, 512, "%s/address", sysfs_path);
+  fp = fopen (buf, "r");

Ditto.

+  buf2 = malloc (sizeof (char) * 512);
+
+  if (!buf2)
+    {
+      free (nvmeof_info->host_wwpn);
+      free (nvmeof_info->target_wwpn);
+      free (nvmeof_info->nqn);
+      free (buf);
+      return -1;
+    }
+
+  fscanf (fp, "%s", buf2);

Ditto.

+  fclose (fp);
+
+  buf3 = strrchr (buf2, '-') + 1;

Missing check for strrchr() != NULL so that buf3 may be assigned invalid
address "1". This is very likely to happen given no check for buf2 read
from file is successful.

+  grub_memcpy (nvmeof_info->host_wwpn, buf3, 256);

The strrchr()/strchr() may return NULL if the characters being searched
is not present. As a consequence this will cause segvfault by reading
illegal address "1".

+  buf3=strchr (buf2, '-') + 1;
+  buf3=strchr (buf3, '-') + 1;
+  buf3=strchr (buf3, 'x') + 1;
+  grub_memcpy (nvmeof_info->target_wwpn, buf3, 256);

Ditto.

+  buf3 = strchr (nvmeof_info->target_wwpn, ',');
+  *buf3 = '\0';

The buf3 != NULL check is missing before dereference.

+  free (buf);
+  free (buf2);
+  return 0;
+}
+
+#define MAX_NVME_NSID_DIGITS 6
+
+static char *
+of_path_get_nvme_controller_name_node (const char* devname)
+{
+  char *controller_node, *end;
+
+  controller_node = strdup (devname);
+  end = grub_strchr (controller_node + 1, 'n');
+  if (end != NULL)
+    {
+      *end = '\0';
+    }
+
+  return controller_node;
+}
+
+unsigned int
+of_path_get_nvme_nsid (const char* devname)
+{
+  unsigned int nsid;
+  char *sysfs_path, *buf;
+  FILE *fp;
+
+  buf = malloc (sizeof(char) * 512);
+  if (!buf)
+    return 0;
+
+  sysfs_path = block_device_get_sysfs_path_and_link (devname);
+  snprintf (buf, 512, "%s/%s/nsid", sysfs_path, devname);
+  fp = fopen(buf, "r");
+  fscanf (fp, "%u", &(nsid));
+  fclose (fp);

Ditto

+
+  free (sysfs_path);
+  free (buf);
+  return nsid;
+}
+
+static char *
+nvme_get_syspath (const char *nvmedev)
+{
+  char *sysfs_path, *controller_node;
+
+  sysfs_path = block_device_get_sysfs_path_and_link (nvmedev);
+  if (strstr (sysfs_path, "nvme-subsystem"))
+    {
+ controller_node = of_path_get_nvme_controller_name_node (nvmedev);
+      strcat (sysfs_path, "/");
+      strcat (sysfs_path, controller_node);

The strcat() would lead to out-of-bounds writes as the destination
buffer, sysfs_path, didn't have more space to cancat any new string.

Thanks,
Michael

+      sysfs_path = xrealpath (sysfs_path);
+    }
+
+  return sysfs_path;
+}
+
 static char *
 of_path_of_nvme(const char *sys_devname __attribute__((unused)),
                const char *device,
@@ -391,6 +670,8 @@ of_path_of_nvme(const char *sys_devname __attribute__((unused)),
 {
   char *sysfs_path, *of_path, disk[MAX_DISK_CAT];
   const char *digit_string, *part_end;
+  int chars_written, ret_val;
+  struct ofpath_nvmeof_info* nvmeof_info;

   digit_string = trailing_digits (device);
   part_end = devicenode + strlen (devicenode) - 1;
@@ -410,15 +691,90 @@ of_path_of_nvme(const char *sys_devname __attribute__((unused)),
       /* Remove the p. */
       *end = '\0';
       sscanf (digit_string, "%d", &part);
-      snprintf (disk, sizeof (disk), "/disk@1:%c", 'a' + (part - 1));
-      sysfs_path = block_device_get_sysfs_path_and_link (nvmedev);
+      sysfs_path = nvme_get_syspath (nvmedev);
+
+      /* If is a NVMeoF */
+      if (strstr (sysfs_path, "nvme-fabrics"))
+        {
+          nvmeof_info = malloc (sizeof (struct ofpath_nvmeof_info));
+          if (!nvmeof_info)
+            {
+              free (nvmedev);
+              return NULL;
+            }
+
+ ret_val = of_path_get_nvmeof_adapter_info (sysfs_path, nvmeof_info);
+          if (ret_val == -1)
+            {
+              free (nvmedev);
+              free (nvmeof_info);
+              return NULL;
+            }
+
+          sysfs_path = of_find_fc_host (nvmeof_info->host_wwpn);
+          if (!sysfs_path)
+            {
+              free (nvmedev);
+              free (nvmeof_info);
+              return NULL;
+            }
+
+ chars_written = snprintf (disk,sizeof(disk), "/nvme-of/controller@%s,%x:nqn=%s",
+                                    nvmeof_info->target_wwpn,0xffff,
+                                    nvmeof_info->nqn);
+          unsigned int nsid = of_path_get_nvme_nsid (nvmedev);
+          if (nsid)
+            {
+ snprintf (disk+chars_written, sizeof("/namespace@") + MAX_NVME_NSID_DIGITS,
+                        "/namespace@%x:%d", nsid, part);
+            }
+          free (nvmeof_info);
+        }
+      else
+        {
+ snprintf (disk, sizeof (disk), "/disk@1:%c", 'a' + (part - 1));
+        }
       free (nvmedev);
     }
   else
     {
       /* We do not have the parition. */
-      snprintf (disk, sizeof (disk), "/disk@1");
-      sysfs_path = block_device_get_sysfs_path_and_link (device);
+      sysfs_path = nvme_get_syspath (device);
+      if (strstr (sysfs_path, "nvme-fabrics"))
+        {
+          nvmeof_info = malloc (sizeof (struct ofpath_nvmeof_info));
+          if (!nvmeof_info)
+            return NULL;
+
+ ret_val = of_path_get_nvmeof_adapter_info (sysfs_path, nvmeof_info);
+          if (ret_val == -1)
+            {
+              free (nvmeof_info);
+              return NULL;
+            }
+
+          sysfs_path = of_find_fc_host (nvmeof_info->host_wwpn);
+          if (!sysfs_path)
+            {
+              free (nvmeof_info);
+              return NULL;
+            }
+
+ chars_written = snprintf (disk,sizeof(disk), "/nvme-of/controller@%s,%x:nqn=%s",
+                                    nvmeof_info->target_wwpn, 0xffff,
+                                    nvmeof_info->nqn);
+          unsigned int nsid = of_path_get_nvme_nsid (device);
+          if (nsid)
+            {
+ snprintf (disk+chars_written,sizeof("/namespace@") + sizeof(char) * MAX_NVME_NSID_DIGITS,
+                        "/namespace@%x", nsid);
+            }
+          free (nvmeof_info);
+        }
+      else
+        {
+          snprintf (disk, sizeof (disk), "/disk@1");
+        }
     }

   of_path = find_obppath (sysfs_path);
@@ -429,7 +785,6 @@ of_path_of_nvme(const char *sys_devname __attribute__((unused)),
   free (sysfs_path);
   return of_path;
 }
-#endif

 static int
 vendor_is_ATA(const char *path)
@@ -779,11 +1134,9 @@ grub_util_devname_to_ofpath (const char *sys_devname)
     /* All the models I've seen have a devalias "floppy".
        New models have no floppy at all. */
     ofpath = xstrdup ("floppy");
-#ifdef __sparc__
   else if (device[0] == 'n' && device[1] == 'v' && device[2] == 'm'
            && device[3] == 'e')
     ofpath = of_path_of_nvme (name_buf, device, devnode, devicenode);
-#endif
   else
     {
       grub_util_warn (_("unknown device type %s"), device);
diff --git a/include/grub/util/ofpath.h b/include/grub/util/ofpath.h
index b43c523..85172bc 100644
--- a/include/grub/util/ofpath.h
+++ b/include/grub/util/ofpath.h
@@ -3,4 +3,32 @@

 char *grub_util_devname_to_ofpath (const char *devname);

+struct ofpath_files_list_node
+{
+  char* filename;
+  struct ofpath_files_list_node* next;
+};
+
+struct ofpath_files_list_root
+{
+  int items;
+  struct ofpath_files_list_node* first;
+};
+
+struct ofpath_nvmeof_info
+{
+  char* host_wwpn;
+  char* target_wwpn;
+  char* nqn;
+  int cntlid;
+  int nsid;
+};
+
+int of_path_get_nvmeof_adapter_info (char* sysfs_path, struct ofpath_nvmeof_info* nvmeof_info);
+unsigned int of_path_get_nvme_nsid (const char* devname);
+int add_filename_to_pile (char *filename, struct ofpath_files_list_root* root); +void find_file (char* filename, char* directory, struct ofpath_files_list_root* root, int max_depth, int depth);
+char* of_find_fc_host (char* host_wwpn);
+void free_ofpath_files_list (struct ofpath_files_list_root* root);
+
 #endif /* ! GRUB_OFPATH_MACHINE_UTIL_HEADER */
--
2.31.1

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