Re: [PATCH] proc/vmcore: fix potential memory leak in vmcore_init()
On 09/13/22 at 07:35am, Matthew Wilcox wrote:
> On Tue, Sep 13, 2022 at 02:25:01PM +0800, Jianglei Nie wrote:
> > }
> > - 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;
> > }
>
> Did you test this? It looks like you now call
> elfcorehdr_free(ELFCORE_ADDR_ERR) if 'rc' is 0.
Right, that will cause problem. It's my fault since I suggested
the current change.
Jianglei, please use your v1 change and post again. Sorry for the
incorrect suggestion.
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Re: [PATCH] proc/vmcore: fix potential memory leak in vmcore_init()
On Tue, Sep 13, 2022 at 02:25:01PM +0800, Jianglei Nie wrote:
> }
> - 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;
> }
Did you test this? It looks like you now call
elfcorehdr_free(ELFCORE_ADDR_ERR) if 'rc' is 0.
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[PATCH] proc/vmcore: fix potential memory leak in vmcore_init()
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() gets some error and
returns a negetive value, the elfcorehdr_addr should be released with
elfcorehdr_free().
Fix it by calling elfcorehdr_free() when parse_crash_elf_headers() fails.
Acked-by: Baoquan He
Signed-off-by: Jianglei Nie
---
fs/proc/vmcore.c | 8 +---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index f2aa86c421f2..163cb266f5fd 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1568,15 +1568,17 @@ 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
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Re: [PATCH] proc/vmcore: fix potential memory leak in vmcore_init()
On 06/30/22 at 12:52am, 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
> 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
> ---
> fs/proc/vmcore.c | 1 +
> 1 file changed, 1 insertion(+)
>
> diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
> index 4eaeb645e759..7e028cd1e59d 100644
> --- a/fs/proc/vmcore.c
> +++ b/fs/proc/vmcore.c
> @@ -1568,6 +1568,7 @@ static int __init vmcore_init(void)
> return rc;
> rc = parse_crash_elf_headers();
> if (rc) {
> + elfcorehdr_free(elfcorehdr_addr);
> pr_warn("Kdump: vmcore not initialized\n");
> return rc;
Guess it's found by code inspecting since if vmcore_init() failed, kdump
kernel won't do anyting meaningful and reboot, then nobody notice or
care about this leak.
If so, is this better?
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 7e028cd1e59d..ea2f44d77786 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1568,16 +1568,16 @@ static int __init vmcore_init(void)
return rc;
rc = parse_crash_elf_headers();
if (rc) {
- elfcorehdr_free(elfcorehdr_addr);
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;
+fail:
+ elfcorehdr_free(elfcorehdr_addr);
return 0;
}
fs_initcall(vmcore_init);
> }
> --
> 2.25.1
>
>
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[PATCH] proc/vmcore: fix potential memory leak in vmcore_init()
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
---
fs/proc/vmcore.c | 1 +
1 file changed, 1 insertion(+)
diff --git a/fs/proc/vmcore.c b/fs/proc/vmcore.c
index 4eaeb645e759..7e028cd1e59d 100644
--- a/fs/proc/vmcore.c
+++ b/fs/proc/vmcore.c
@@ -1568,6 +1568,7 @@ static int __init vmcore_init(void)
return rc;
rc = parse_crash_elf_headers();
if (rc) {
+ elfcorehdr_free(elfcorehdr_addr);
pr_warn("Kdump: vmcore not initialized\n");
return rc;
}
--
2.25.1
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