[PATCH 0/4] Adding a failure check after grub_malloc()

[PATCH 0/4] Adding a failure check after grub_malloc()

[Avnish Chouhan]

This patch series adds a NULL check after calling grub_malloc().
Missing a failure check after calling grub_malloc() can lead to undefined
behavior. If the allocation fails and returns NULL, subsequent dereferencing
or writing to the pointer will likely result in a runtime error such as
a segmentation fault.

Patch 1/4 (0001-normal-Adding-a-grub_malloc-failure-check-in-completion-c.patch)
Patch 2/4 (0002-Adding-a-grub_malloc-failure-check-in-msdos-c.patch)
Patch 3/4 (0003-Adding-a-grub_malloc-failure-check-in-mmap-c.patch)
Patch 4/4 (0004-Adding-a-grub_malloc-failure-check-in-legacy_parse-c.patch) 

Avnish Chouhan (4):
 normal: Adding a grub_malloc failure check in completion.c
 Adding a grub_malloc failure check in msdos.c
 Adding a grub_malloc failure check in mmap.c
 Adding a grub_malloc failure check in legacy_parse.c

 grub-core/normal/completion.c | 3 +++
 grub-core/partmap/msdos.c     | 3 +++
 grub-core/mmap/mmap.c         | 3 +++
 grub-core/lib/legacy_parse.c  | 3 +++
 4 files changed

-- 
2.31.1


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[PATCH 1/4] normal: Adding a grub_malloc failure check in completion.c

[Avnish Chouhan]

This patch adds a NULL check in grub_malloc(). Missing a failure check
after calling grub_malloc() can lead to undefined behavior. If the allocation
fails and returns NULL, subsequent dereferencing or writing to the pointer
will likely result in a runtime error such as a segmentation fault.

Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
---
 grub-core/normal/completion.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/normal/completion.c b/grub-core/normal/completion.c
index 18cadfa..4058e0a 100644
--- a/grub-core/normal/completion.c
+++ b/grub-core/normal/completion.c
@@ -490,6 +490,9 @@ grub_normal_do_completion (char *buf, int *restore,
 	  spaces++;
 
       ret = grub_malloc (match_len - current_len + grub_strlen (suffix) + spaces + 1);
+      if (ret == NULL)
+        goto fail;
+
       newstr = ret;
       for (escstr = match + current_len; *escstr; escstr++)
 	{
-- 
2.47.1


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Re: [PATCH 1/4] normal: Adding a grub_malloc failure check in completion.c

[Sudhakar Kuppusamy]

On 28 Oct 2025, at 10:01 PM, Avnish Chouhan <avnish@linux.ibm.com> wrote:
> 
> This patch adds a NULL check in grub_malloc(). Missing a failure check
> after calling grub_malloc() can lead to undefined behavior. If the allocation
> fails and returns NULL, subsequent dereferencing or writing to the pointer
> will likely result in a runtime error such as a segmentation fault.
> 
> Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>

Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Thanks,
Sudhakar  
> ---
> grub-core/normal/completion.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/grub-core/normal/completion.c b/grub-core/normal/completion.c
> index 18cadfa..4058e0a 100644
> --- a/grub-core/normal/completion.c
> +++ b/grub-core/normal/completion.c
> @@ -490,6 +490,9 @@ grub_normal_do_completion (char *buf, int *restore,
>  spaces++;
> 
>       ret = grub_malloc (match_len - current_len + grub_strlen (suffix) + spaces + 1);
> +      if (ret == NULL)
> +        goto fail;
> +
>       newstr = ret;
>       for (escstr = match + current_len; *escstr; escstr++)
> {
> -- 
> 2.47.1
> 
> 
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[PATCH 2/4] Adding a grub_malloc failure check in msdos.c

[Avnish Chouhan]

Adding a NULL check in grub_malloc(). Missing a failure check after calling grub_malloc() can lead to
undefined behavior. If the allocation fails and returns NULL, subsequent
dereferencing or writing to the pointer will likely result in a runtime
error such as a segmentation fault.

Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
---
 grub-core/partmap/msdos.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
index c85bb74..bf92617 100644
--- a/grub-core/partmap/msdos.c
+++ b/grub-core/partmap/msdos.c
@@ -348,6 +348,9 @@ pc_partition_map_embed (struct grub_disk *disk, unsigned int *nsectors,
        * area.
        */
       embed_signature_check = grub_malloc (GRUB_DISK_SECTOR_SIZE);
+      if (embed_signature_check == NULL)
+        return grub_errno;
+
       for (i = 0; i < *nsectors; i++)
 	{
 	  if (grub_disk_read (disk, (*sectors)[i], 0, GRUB_DISK_SECTOR_SIZE,
-- 
2.47.1


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Re: [PATCH 2/4] Adding a grub_malloc failure check in msdos.c

[Sudhakar Kuppusamy]

> On 28 Oct 2025, at 10:02 PM, Avnish Chouhan <avnish@linux.ibm.com> wrote:
> 
> Adding a NULL check in grub_malloc(). Missing a failure check after calling grub_malloc() can lead to
> undefined behavior. If the allocation fails and returns NULL, subsequent
> dereferencing or writing to the pointer will likely result in a runtime
> error such as a segmentation fault.
> 
> Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>

Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Thanks,
Sudhakar  
> ---
> grub-core/partmap/msdos.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/grub-core/partmap/msdos.c b/grub-core/partmap/msdos.c
> index c85bb74..bf92617 100644
> --- a/grub-core/partmap/msdos.c
> +++ b/grub-core/partmap/msdos.c
> @@ -348,6 +348,9 @@ pc_partition_map_embed (struct grub_disk *disk, unsigned int *nsectors,
>        * area.
>        */
>       embed_signature_check = grub_malloc (GRUB_DISK_SECTOR_SIZE);
> +      if (embed_signature_check == NULL)
> +        return grub_errno;
> +
>       for (i = 0; i < *nsectors; i++)
> {
>  if (grub_disk_read (disk, (*sectors)[i], 0, GRUB_DISK_SECTOR_SIZE,
> -- 
> 2.47.1
> 
> 
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[PATCH 3/4] Adding a grub_malloc failure check in mmap.c

[Avnish Chouhan]

Adding a failure check after calling grub_malloc() as it can lead to
undefined behavior. If the allocation fails and returns NULL, subsequent
dereferencing or writing to the pointer will likely result in a runtime
error such as a segmentation fault.

Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
---
 grub-core/mmap/mmap.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/mmap/mmap.c b/grub-core/mmap/mmap.c
index c8c8312..8f03b77 100644
--- a/grub-core/mmap/mmap.c
+++ b/grub-core/mmap/mmap.c
@@ -242,6 +242,9 @@ grub_mmap_iterate (grub_memory_hook_t hook, void *hook_data)
 	  else
 	    {
 	      struct mm_list *n = grub_malloc (sizeof (*n));
+              if (n == NULL)
+                return grub_errno;
+
 	      n->val = ctx.scanline_events[i].memtype;
 	      n->present = 1;
 	      n->next = present[ctx.scanline_events[i].priority].next;
-- 
2.47.1


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Re: [PATCH 3/4] Adding a grub_malloc failure check in mmap.c

[Sudhakar Kuppusamy]

> On 28 Oct 2025, at 10:02 PM, Avnish Chouhan <avnish@linux.ibm.com> wrote:
> 
> Adding a failure check after calling grub_malloc() as it can lead to
> undefined behavior. If the allocation fails and returns NULL, subsequent
> dereferencing or writing to the pointer will likely result in a runtime
> error such as a segmentation fault.
> 
> Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>

Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Thanks,
Sudhakar  
> ---
> grub-core/mmap/mmap.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/grub-core/mmap/mmap.c b/grub-core/mmap/mmap.c
> index c8c8312..8f03b77 100644
> --- a/grub-core/mmap/mmap.c
> +++ b/grub-core/mmap/mmap.c
> @@ -242,6 +242,9 @@ grub_mmap_iterate (grub_memory_hook_t hook, void *hook_data)
>  else
>    {
>      struct mm_list *n = grub_malloc (sizeof (*n));
> +              if (n == NULL)
> +                return grub_errno;
> +
>      n->val = ctx.scanline_events[i].memtype;
>      n->present = 1;
>      n->next = present[ctx.scanline_events[i].priority].next;
> -- 
> 2.47.1
> 
> 
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[PATCH 4/4] Adding a grub_malloc failure check in legacy_parse.c

[Avnish Chouhan]

Adding a failure check after calling grub_malloc() as it can lead to
undefined behavior. If the allocation fails and returns NULL, subsequent
dereferencing or writing to the pointer will likely result in a runtime
error such as a segmentation fault.

Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>
---
 grub-core/lib/legacy_parse.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/grub-core/lib/legacy_parse.c b/grub-core/lib/legacy_parse.c
index fa0131a..8995309 100644
--- a/grub-core/lib/legacy_parse.c
+++ b/grub-core/lib/legacy_parse.c
@@ -508,6 +508,9 @@ grub_legacy_parse (const char *buf, char **entryname, char **suffix)
       char *ret;
       int len = grub_strlen (buf);
       ret = grub_malloc (len + 2);
+      if (ret == NULL)
+        return NULL;
+
       grub_memcpy (ret, buf, len);
       if (len && ret[len - 1] == '\n')
 	ret[len] = 0;
-- 
2.47.1


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Re: [PATCH 4/4] Adding a grub_malloc failure check in legacy_parse.c

[Sudhakar Kuppusamy]

> On 28 Oct 2025, at 10:02 PM, Avnish Chouhan <avnish@linux.ibm.com> wrote:
> 
> Adding a failure check after calling grub_malloc() as it can lead to
> undefined behavior. If the allocation fails and returns NULL, subsequent
> dereferencing or writing to the pointer will likely result in a runtime
> error such as a segmentation fault.
> 
> Signed-off-by: Avnish Chouhan <avnish@linux.ibm.com>

Reviewed-by: Sudhakar Kuppusamy <sudhakar@linux.ibm.com>

Thanks,
Sudhakar  
> ---
> grub-core/lib/legacy_parse.c | 3 +++
> 1 file changed, 3 insertions(+)
> 
> diff --git a/grub-core/lib/legacy_parse.c b/grub-core/lib/legacy_parse.c
> index fa0131a..8995309 100644
> --- a/grub-core/lib/legacy_parse.c
> +++ b/grub-core/lib/legacy_parse.c
> @@ -508,6 +508,9 @@ grub_legacy_parse (const char *buf, char **entryname, char **suffix)
>       char *ret;
>       int len = grub_strlen (buf);
>       ret = grub_malloc (len + 2);
> +      if (ret == NULL)
> +        return NULL;
> +
>       grub_memcpy (ret, buf, len);
>       if (len && ret[len - 1] == '\n')
> ret[len] = 0;
> -- 
> 2.47.1
> 
> 
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Re: [PATCH 0/4] Adding a failure check after grub_malloc()

[Daniel Kiper]

On Tue, Oct 28, 2025 at 10:01:58PM +0530, Avnish Chouhan wrote:
> This patch series adds a NULL check after calling grub_malloc().
> Missing a failure check after calling grub_malloc() can lead to undefined
> behavior. If the allocation fails and returns NULL, subsequent dereferencing
> or writing to the pointer will likely result in a runtime error such as
> a segmentation fault.
>
> Patch 1/4 (0001-normal-Adding-a-grub_malloc-failure-check-in-completion-c.patch)
> Patch 2/4 (0002-Adding-a-grub_malloc-failure-check-in-msdos-c.patch)
> Patch 3/4 (0003-Adding-a-grub_malloc-failure-check-in-mmap-c.patch)
> Patch 4/4 (0004-Adding-a-grub_malloc-failure-check-in-legacy_parse-c.patch)
>
> Avnish Chouhan (4):
>  normal: Adding a grub_malloc failure check in completion.c
>  Adding a grub_malloc failure check in msdos.c
>  Adding a grub_malloc failure check in mmap.c
>  Adding a grub_malloc failure check in legacy_parse.c

For all patches Reviewed-by: Daniel Kiper <daniel.kiper@oracle.com>...

Thank you for fixing these issues!

Daniel

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