[PATCH v4] proc/vmcore: fix potential memory leak in vmcore_init()

[PATCH v4] proc/vmcore: fix potential memory leak in vmcore_init()

[Jianglei Nie]

elfcorehdr_alloc() allocates a memory chunk for elfcorehdr_addr with
kzalloc(). If is_vmcore_usable() returns false, elfcorehdr_addr is a
predefined value. If parse_crash_elf_headers() occurs some error and
returns a negetive value, the elfcorehdr_addr should be released with
elfcorehdr_free().

We can fix by calling elfcorehdr_free() when parse_crash_elf_headers()
fails.

Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
---
 fs/proc/vmcore.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 4eaeb645e759..390515c249dd 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1569,15 +1569,16 @@ static int __init vmcore_init(void)
 	rc = parse_crash_elf_headers();
 	if (rc) {
 		pr_warn("Kdump: vmcore not initialized\n");
-		return rc;
+		goto fail;
 	}
-	elfcorehdr_free(elfcorehdr_addr);
 	elfcorehdr_addr = ELFCORE_ADDR_ERR;
 
 	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
 	if (proc_vmcore)
 		proc_vmcore->size = vmcore_size;
-	return 0;
+fail:
+	elfcorehdr_free(elfcorehdr_addr);
+	return rc;
 }
 fs_initcall(vmcore_init);
 
-- 
2.25.1

Re: [PATCH v4] proc/vmcore: fix potential memory leak in vmcore_init()

[Baoquan He]

On 07/12/22 at 09:00am, Jianglei Nie wrote:
> elfcorehdr_alloc() allocates a memory chunk for elfcorehdr_addr with
> kzalloc(). If is_vmcore_usable() returns false, elfcorehdr_addr is a
> predefined value. If parse_crash_elf_headers() occurs some error and
                                                 ^ s/occurs/gets/
                                           occur is intransitive verb
> returns a negetive value, the elfcorehdr_addr should be released with
> elfcorehdr_free().
> 
> fix by calling elfcorehdr_free() when parse_crash_elf_headers()
> fails.

  Fix it by calling elfcorehdr_free() when parse_crash_elf_headers()
fails.

Other than above log concerns, you can add my ack when repost:

Acked-by: Baoquan He <bhe@redhat.com>

Note:
- Please also add change history so that people know what's happening
  during reviewing. For this one, you can skip it.
- remember adding all people involved to CC.

> 
> Signed-off-by: Jianglei Nie <niejianglei2021@163.com>
> ---
>  fs/proc/vmcore.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index 4eaeb645e759..390515c249dd 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -1569,15 +1569,16 @@ static int __init vmcore_init(void)
>  	rc = parse_crash_elf_headers();
>  	if (rc) {
>  		pr_warn("Kdump: vmcore not initialized\n");
> -		return rc;
> +		goto fail;
>  	}
> -	elfcorehdr_free(elfcorehdr_addr);
>  	elfcorehdr_addr = ELFCORE_ADDR_ERR;
>  
>  	proc_vmcore = proc_create("vmcore", S_IRUSR, NULL, &vmcore_proc_ops);
>  	if (proc_vmcore)
>  		proc_vmcore->size = vmcore_size;
> -	return 0;
> +fail:
> +	elfcorehdr_free(elfcorehdr_addr);
> +	return rc;
>  }
>  fs_initcall(vmcore_init);
>  
> -- 
> 2.25.1
>