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[v2,01/13] ata: libata-core: Fix null pointer dereference on error

Message ID 20240626180031.4050226-16-cassel@kernel.org
State New
Headers show
Series ata,libsas: Assign the unique id used for printing earlier | expand

Commit Message

Niklas Cassel June 26, 2024, 6 p.m. UTC 
If the ata_port_alloc() call in ata_host_alloc() fails,
ata_host_release() will get called.

However, the code in ata_host_release() tries to free ata_port struct
members unconditionally, which can lead to the following:

BUG: unable to handle page fault for address: 0000000000003990
PGD 0 P4D 0
Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44
Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata]
Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41
RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246
RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000
RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0
RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68
R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004
R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006
FS:  00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000
CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0
PKRU: 55555554
Call Trace:
 <TASK>
 ? __die_body.cold+0x19/0x27
 ? page_fault_oops+0x15a/0x2f0
 ? exc_page_fault+0x7e/0x180
 ? asm_exc_page_fault+0x26/0x30
 ? ata_host_release.cold+0x2f/0x6e [libata]
 ? ata_host_release.cold+0x2f/0x6e [libata]
 release_nodes+0x35/0xb0
 devres_release_group+0x113/0x140
 ata_host_alloc+0xed/0x120 [libata]
 ata_host_alloc_pinfo+0x14/0xa0 [libata]
 ahci_init_one+0x6c9/0xd20 [ahci]

Do not access ata_port struct members unconditionally.

Fixes: 633273a3ed1c ("libata-pmp: hook PMP support and enable it")
Cc: stable@vger.kernel.org
Signed-off-by: Niklas Cassel <cassel@kernel.org>
---
 drivers/ata/libata-core.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

Comments

Damien Le Moal June 27, 2024, 1 a.m. UTC | #1 
On 6/27/24 03:00, Niklas Cassel wrote:
> If the ata_port_alloc() call in ata_host_alloc() fails,
> ata_host_release() will get called.
> 
> However, the code in ata_host_release() tries to free ata_port struct
> members unconditionally, which can lead to the following:
> 
> BUG: unable to handle page fault for address: 0000000000003990
> PGD 0 P4D 0
> Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
> RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata]
> Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41
> RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246
> RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0
> RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68
> R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004
> R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006
> FS:  00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0
> PKRU: 55555554
> Call Trace:
>  <TASK>
>  ? __die_body.cold+0x19/0x27
>  ? page_fault_oops+0x15a/0x2f0
>  ? exc_page_fault+0x7e/0x180
>  ? asm_exc_page_fault+0x26/0x30
>  ? ata_host_release.cold+0x2f/0x6e [libata]
>  ? ata_host_release.cold+0x2f/0x6e [libata]
>  release_nodes+0x35/0xb0
>  devres_release_group+0x113/0x140
>  ata_host_alloc+0xed/0x120 [libata]
>  ata_host_alloc_pinfo+0x14/0xa0 [libata]
>  ahci_init_one+0x6c9/0xd20 [ahci]
> 
> Do not access ata_port struct members unconditionally.
> 
> Fixes: 633273a3ed1c ("libata-pmp: hook PMP support and enable it")
> Cc: stable@vger.kernel.org
> Signed-off-by: Niklas Cassel <cassel@kernel.org>

Looks good, with a nit below. This should be queued as soon as possible as a
6.10 fix patch.

Reviewed-by: Damien Le Moal <dlemoal@kernel.org>

> ---
>  drivers/ata/libata-core.c | 10 ++++++----
>  1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index e1bf8a19b3c8..88e32f638f33 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -5518,10 +5518,12 @@ static void ata_host_release(struct kref *kref)
>  	for (i = 0; i < host->n_ports; i++) {
>  		struct ata_port *ap = host->ports[i];
>  
> -		kfree(ap->pmp_link);
> -		kfree(ap->slave_link);
> -		kfree(ap->ncq_sense_buf);
> -		kfree(ap);
> +		if (ap) {
> +			kfree(ap->pmp_link);
> +			kfree(ap->slave_link);
> +			kfree(ap->ncq_sense_buf);
> +			kfree(ap);
> +		}
>  		host->ports[i] = NULL;

Nit: this line can go inside the if as well. Or even better: reverse the if
condition and continue to ignore NULL ports.

	for (i = 0; i < host->n_ports; i++) {
  		struct ata_port *ap = host->ports[i];

		if (!ap)
			continue;

		kfree(ap->pmp_link);
		kfree(ap->slave_link);
		kfree(ap->ncq_sense_buf);
		kfree(ap);
		host->ports[i] = NULL;
	}
Hannes Reinecke June 27, 2024, 6:24 a.m. UTC | #2 
On 6/26/24 20:00, Niklas Cassel wrote:
> If the ata_port_alloc() call in ata_host_alloc() fails,
> ata_host_release() will get called.
> 
> However, the code in ata_host_release() tries to free ata_port struct
> members unconditionally, which can lead to the following:
> 
> BUG: unable to handle page fault for address: 0000000000003990
> PGD 0 P4D 0
> Oops: Oops: 0000 [#1] PREEMPT SMP NOPTI
> CPU: 10 PID: 594 Comm: (udev-worker) Not tainted 6.10.0-rc5 #44
> Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.16.3-2.fc40 04/01/2014
> RIP: 0010:ata_host_release.cold+0x2f/0x6e [libata]
> Code: e4 4d 63 f4 44 89 e2 48 c7 c6 90 ad 32 c0 48 c7 c7 d0 70 33 c0 49 83 c6 0e 41
> RSP: 0018:ffffc90000ebb968 EFLAGS: 00010246
> RAX: 0000000000000041 RBX: ffff88810fb52e78 RCX: 0000000000000000
> RDX: 0000000000000000 RSI: ffff88813b3218c0 RDI: ffff88813b3218c0
> RBP: ffff88810fb52e40 R08: 0000000000000000 R09: 6c65725f74736f68
> R10: ffffc90000ebb738 R11: 73692033203a746e R12: 0000000000000004
> R13: 0000000000000000 R14: 0000000000000011 R15: 0000000000000006
> FS:  00007f6cc55b9980(0000) GS:ffff88813b300000(0000) knlGS:0000000000000000
> CS:  0010 DS: 0000 ES: 0000 CR0: 0000000080050033
> CR2: 0000000000003990 CR3: 00000001122a2000 CR4: 0000000000750ef0
> PKRU: 55555554
> Call Trace:
>   <TASK>
>   ? __die_body.cold+0x19/0x27
>   ? page_fault_oops+0x15a/0x2f0
>   ? exc_page_fault+0x7e/0x180
>   ? asm_exc_page_fault+0x26/0x30
>   ? ata_host_release.cold+0x2f/0x6e [libata]
>   ? ata_host_release.cold+0x2f/0x6e [libata]
>   release_nodes+0x35/0xb0
>   devres_release_group+0x113/0x140
>   ata_host_alloc+0xed/0x120 [libata]
>   ata_host_alloc_pinfo+0x14/0xa0 [libata]
>   ahci_init_one+0x6c9/0xd20 [ahci]
> 
> Do not access ata_port struct members unconditionally.
> 
> Fixes: 633273a3ed1c ("libata-pmp: hook PMP support and enable it")
> Cc: stable@vger.kernel.org
> Signed-off-by: Niklas Cassel <cassel@kernel.org>
> ---
>   drivers/ata/libata-core.c | 10 ++++++----
>   1 file changed, 6 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
> index e1bf8a19b3c8..88e32f638f33 100644
> --- a/drivers/ata/libata-core.c
> +++ b/drivers/ata/libata-core.c
> @@ -5518,10 +5518,12 @@ static void ata_host_release(struct kref *kref)
>   	for (i = 0; i < host->n_ports; i++) {
>   		struct ata_port *ap = host->ports[i];
>   
> -		kfree(ap->pmp_link);
> -		kfree(ap->slave_link);
> -		kfree(ap->ncq_sense_buf);
> -		kfree(ap);
> +		if (ap) {
> +			kfree(ap->pmp_link);
> +			kfree(ap->slave_link);
> +			kfree(ap->ncq_sense_buf);
> +			kfree(ap);
> +		}
>   		host->ports[i] = NULL;
>   	}
>   	kfree(host);
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
diff mbox series

Patch

diff --git a/drivers/ata/libata-core.c b/drivers/ata/libata-core.c
index e1bf8a19b3c8..88e32f638f33 100644
--- a/drivers/ata/libata-core.c
+++ b/drivers/ata/libata-core.c
@@ -5518,10 +5518,12 @@  static void ata_host_release(struct kref *kref)
 	for (i = 0; i < host->n_ports; i++) {
 		struct ata_port *ap = host->ports[i];
 
-		kfree(ap->pmp_link);
-		kfree(ap->slave_link);
-		kfree(ap->ncq_sense_buf);
-		kfree(ap);
+		if (ap) {
+			kfree(ap->pmp_link);
+			kfree(ap->slave_link);
+			kfree(ap->ncq_sense_buf);
+			kfree(ap);
+		}
 		host->ports[i] = NULL;
 	}
 	kfree(host);