* [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
@ 2024-09-17 15:08 Alper Nebi Yasak
2024-09-17 16:30 ` Andy Shevchenko
` (2 more replies)
0 siblings, 3 replies; 6+ messages in thread
From: Alper Nebi Yasak @ 2024-09-17 15:08 UTC (permalink / raw)
To: linux-wireless, linux-kernel
Cc: David Lin, Dmitry Antipov, Brian Norris, Kalle Valo,
Francesco Dolcini, Sascha Hauer, Kees Cook, Gustavo A . R . Silva,
Andy Shevchenko, Johannes Berg, Alper Nebi Yasak
Replace one-element array with a flexible-array member in `struct
mwifiex_ie_types_wildcard_ssid_params` to fix the following warning
on a MT8173 Chromebook (mt8173-elm-hana):
[ 356.775250] ------------[ cut here ]------------
[ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1)
[ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
The "(size 6)" above is exactly the length of the SSID of the network
this device was connected to. The source of the warning looks like:
ssid_len = user_scan_in->ssid_list[i].ssid_len;
[...]
memcpy(wildcard_ssid_tlv->ssid,
user_scan_in->ssid_list[i].ssid, ssid_len);
Also adjust a #define that uses sizeof() on this struct to keep the
value same as before.
Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
---
I found these relevant patches that modify other such arrays, where the
second one removes a -1 from some sizeof() calculation:
https://lore.kernel.org/lkml/Y9xkECG3uTZ6T1dN@work/T/#u
https://lore.kernel.org/lkml/ZsZa5xRcsLq9D+RX@elsanto/T/#u
So I think we need the +1 to keep things same. But it appears to work
fine without it, so I'm not sure. Maybe it should've had a -1 before
that I would remove with this?
drivers/net/wireless/marvell/mwifiex/fw.h | 2 +-
drivers/net/wireless/marvell/mwifiex/scan.c | 2 +-
2 files changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
index d03129d5d24e..4a96281792cc 100644
--- a/drivers/net/wireless/marvell/mwifiex/fw.h
+++ b/drivers/net/wireless/marvell/mwifiex/fw.h
@@ -875,7 +875,7 @@ struct mwifiex_ietypes_chanstats {
struct mwifiex_ie_types_wildcard_ssid_params {
struct mwifiex_ie_types_header header;
u8 max_ssid_length;
- u8 ssid[1];
+ u8 ssid[];
} __packed;
#define TSF_DATA_SIZE 8
diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
index cab889af4c4a..50af78ee935b 100644
--- a/drivers/net/wireless/marvell/mwifiex/scan.c
+++ b/drivers/net/wireless/marvell/mwifiex/scan.c
@@ -32,7 +32,7 @@
#define WILDCARD_SSID_TLV_MAX_SIZE \
(MWIFIEX_MAX_SSID_LIST_LENGTH * \
(sizeof(struct mwifiex_ie_types_wildcard_ssid_params) \
- + IEEE80211_MAX_SSID_LEN))
+ + IEEE80211_MAX_SSID_LEN + 1))
/* Maximum memory needed for a mwifiex_scan_cmd_config with all TLVs at max */
#define MAX_SCAN_CFG_ALLOC (sizeof(struct mwifiex_scan_cmd_config) \
base-commit: 4f3e012d4cfd1d9bf837870c961f462ca9f23ebe
--
2.45.2
^ permalink raw reply related [flat|nested] 6+ messages in thread
* Re: [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
2024-09-17 15:08 [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan() Alper Nebi Yasak
@ 2024-09-17 16:30 ` Andy Shevchenko
2024-09-17 17:01 ` Dmitry Antipov
2024-09-17 18:10 ` Jeff Johnson
2024-10-04 23:24 ` Brian Norris
2 siblings, 1 reply; 6+ messages in thread
From: Andy Shevchenko @ 2024-09-17 16:30 UTC (permalink / raw)
To: Alper Nebi Yasak
Cc: linux-wireless, linux-kernel, David Lin, Dmitry Antipov,
Brian Norris, Kalle Valo, Francesco Dolcini, Sascha Hauer,
Kees Cook, Gustavo A . R . Silva, Johannes Berg
On Tue, Sep 17, 2024 at 06:08:41PM +0300, Alper Nebi Yasak wrote:
> Replace one-element array with a flexible-array member in `struct
> mwifiex_ie_types_wildcard_ssid_params` to fix the following warning
> on a MT8173 Chromebook (mt8173-elm-hana):
>
> [ 356.775250] ------------[ cut here ]------------
> [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1)
> [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
>
> The "(size 6)" above is exactly the length of the SSID of the network
> this device was connected to. The source of the warning looks like:
>
> ssid_len = user_scan_in->ssid_list[i].ssid_len;
> [...]
> memcpy(wildcard_ssid_tlv->ssid,
> user_scan_in->ssid_list[i].ssid, ssid_len);
>
> Also adjust a #define that uses sizeof() on this struct to keep the
> value same as before.
...
> #define WILDCARD_SSID_TLV_MAX_SIZE \
> (MWIFIEX_MAX_SSID_LIST_LENGTH * \
> (sizeof(struct mwifiex_ie_types_wildcard_ssid_params) \
> - + IEEE80211_MAX_SSID_LEN))
> + + IEEE80211_MAX_SSID_LEN + 1))
>
This hunk has to be carefully checked by wireless people. I'm not sure
that we need + 1 here.
Otherwise, LGTM.
--
With Best Regards,
Andy Shevchenko
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
2024-09-17 16:30 ` Andy Shevchenko
@ 2024-09-17 17:01 ` Dmitry Antipov
0 siblings, 0 replies; 6+ messages in thread
From: Dmitry Antipov @ 2024-09-17 17:01 UTC (permalink / raw)
To: Alper Nebi Yasak
Cc: linux-wireless, linux-kernel, David Lin, Brian Norris, Kalle Valo,
Francesco Dolcini, Sascha Hauer, Kees Cook, Gustavo A . R . Silva,
Johannes Berg, Andy Shevchenko
On 9/17/24 7:30 PM, Andy Shevchenko wrote:
> This hunk has to be carefully checked by wireless people. I'm not sure
> that we need + 1 here.
Well, +1 looks redundant here indeed.
And if you touch this anyway, please also consider '__counted_by(max_ssid_length)'
for 'ssid' (and test your kernel with CONFIG_KASAN enabled of course).
Dmitry
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
2024-09-17 15:08 [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan() Alper Nebi Yasak
2024-09-17 16:30 ` Andy Shevchenko
@ 2024-09-17 18:10 ` Jeff Johnson
2024-09-17 18:21 ` Gustavo A. R. Silva
2024-10-04 23:24 ` Brian Norris
2 siblings, 1 reply; 6+ messages in thread
From: Jeff Johnson @ 2024-09-17 18:10 UTC (permalink / raw)
To: Alper Nebi Yasak, linux-wireless, linux-kernel
Cc: David Lin, Dmitry Antipov, Brian Norris, Kalle Valo,
Francesco Dolcini, Sascha Hauer, Kees Cook, Gustavo A . R . Silva,
Andy Shevchenko, Johannes Berg
On 9/17/2024 8:08 AM, Alper Nebi Yasak wrote:
> Replace one-element array with a flexible-array member in `struct
> mwifiex_ie_types_wildcard_ssid_params` to fix the following warning
> on a MT8173 Chromebook (mt8173-elm-hana):
>
> [ 356.775250] ------------[ cut here ]------------
> [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1)
> [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
>
> The "(size 6)" above is exactly the length of the SSID of the network
> this device was connected to. The source of the warning looks like:
>
> ssid_len = user_scan_in->ssid_list[i].ssid_len;
> [...]
> memcpy(wildcard_ssid_tlv->ssid,
> user_scan_in->ssid_list[i].ssid, ssid_len);
>
> Also adjust a #define that uses sizeof() on this struct to keep the
> value same as before.
>
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
> ---
> I found these relevant patches that modify other such arrays, where the
> second one removes a -1 from some sizeof() calculation:
>
> https://lore.kernel.org/lkml/Y9xkECG3uTZ6T1dN@work/T/#u
> https://lore.kernel.org/lkml/ZsZa5xRcsLq9D+RX@elsanto/T/#u
>
> So I think we need the +1 to keep things same. But it appears to work
> fine without it, so I'm not sure. Maybe it should've had a -1 before
> that I would remove with this?
I think the original code was incorrect and was allocating too much memory.
I do not think WILDCARD_SSID_TLV_MAX_SIZE requires modification.
>
> drivers/net/wireless/marvell/mwifiex/fw.h | 2 +-
> drivers/net/wireless/marvell/mwifiex/scan.c | 2 +-
> 2 files changed, 2 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
> index d03129d5d24e..4a96281792cc 100644
> --- a/drivers/net/wireless/marvell/mwifiex/fw.h
> +++ b/drivers/net/wireless/marvell/mwifiex/fw.h
> @@ -875,7 +875,7 @@ struct mwifiex_ietypes_chanstats {
> struct mwifiex_ie_types_wildcard_ssid_params {
> struct mwifiex_ie_types_header header;
> u8 max_ssid_length;
> - u8 ssid[1];
> + u8 ssid[];
> } __packed;
>
> #define TSF_DATA_SIZE 8
> diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
> index cab889af4c4a..50af78ee935b 100644
> --- a/drivers/net/wireless/marvell/mwifiex/scan.c
> +++ b/drivers/net/wireless/marvell/mwifiex/scan.c
> @@ -32,7 +32,7 @@
> #define WILDCARD_SSID_TLV_MAX_SIZE \
> (MWIFIEX_MAX_SSID_LIST_LENGTH * \
> (sizeof(struct mwifiex_ie_types_wildcard_ssid_params) \
> - + IEEE80211_MAX_SSID_LEN))
> + + IEEE80211_MAX_SSID_LEN + 1))
>
> /* Maximum memory needed for a mwifiex_scan_cmd_config with all TLVs at max */
> #define MAX_SCAN_CFG_ALLOC (sizeof(struct mwifiex_scan_cmd_config) \
>
> base-commit: 4f3e012d4cfd1d9bf837870c961f462ca9f23ebe
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
2024-09-17 18:10 ` Jeff Johnson
@ 2024-09-17 18:21 ` Gustavo A. R. Silva
0 siblings, 0 replies; 6+ messages in thread
From: Gustavo A. R. Silva @ 2024-09-17 18:21 UTC (permalink / raw)
To: Jeff Johnson, Alper Nebi Yasak, linux-wireless, linux-kernel
Cc: David Lin, Dmitry Antipov, Brian Norris, Kalle Valo,
Francesco Dolcini, Sascha Hauer, Kees Cook, Gustavo A . R . Silva,
Andy Shevchenko, Johannes Berg
On 17/09/24 20:10, Jeff Johnson wrote:
> On 9/17/2024 8:08 AM, Alper Nebi Yasak wrote:
>> Replace one-element array with a flexible-array member in `struct
>> mwifiex_ie_types_wildcard_ssid_params` to fix the following warning
>> on a MT8173 Chromebook (mt8173-elm-hana):
>>
>> [ 356.775250] ------------[ cut here ]------------
>> [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1)
>> [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
>>
>> The "(size 6)" above is exactly the length of the SSID of the network
>> this device was connected to. The source of the warning looks like:
>>
>> ssid_len = user_scan_in->ssid_list[i].ssid_len;
>> [...]
>> memcpy(wildcard_ssid_tlv->ssid,
>> user_scan_in->ssid_list[i].ssid, ssid_len);
>>
>> Also adjust a #define that uses sizeof() on this struct to keep the
>> value same as before.
>>
>> Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
>> ---
>> I found these relevant patches that modify other such arrays, where the
>> second one removes a -1 from some sizeof() calculation:
>>
>> https://lore.kernel.org/lkml/Y9xkECG3uTZ6T1dN@work/T/#u
>> https://lore.kernel.org/lkml/ZsZa5xRcsLq9D+RX@elsanto/T/#u
>>
>> So I think we need the +1 to keep things same. But it appears to work
>> fine without it, so I'm not sure. Maybe it should've had a -1 before
>> that I would remove with this?
>
> I think the original code was incorrect and was allocating too much memory.
> I do not think WILDCARD_SSID_TLV_MAX_SIZE requires modification.
If this is case, I think the changelog text should include the following
'Fixes' tag (and the `__counted_by` annotation added in a separate patch):
Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver")
Thanks
--
Gustavo
>
>>
>> drivers/net/wireless/marvell/mwifiex/fw.h | 2 +-
>> drivers/net/wireless/marvell/mwifiex/scan.c | 2 +-
>> 2 files changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/net/wireless/marvell/mwifiex/fw.h b/drivers/net/wireless/marvell/mwifiex/fw.h
>> index d03129d5d24e..4a96281792cc 100644
>> --- a/drivers/net/wireless/marvell/mwifiex/fw.h
>> +++ b/drivers/net/wireless/marvell/mwifiex/fw.h
>> @@ -875,7 +875,7 @@ struct mwifiex_ietypes_chanstats {
>> struct mwifiex_ie_types_wildcard_ssid_params {
>> struct mwifiex_ie_types_header header;
>> u8 max_ssid_length;
>> - u8 ssid[1];
>> + u8 ssid[];
>> } __packed;
>>
>> #define TSF_DATA_SIZE 8
>> diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c
>> index cab889af4c4a..50af78ee935b 100644
>> --- a/drivers/net/wireless/marvell/mwifiex/scan.c
>> +++ b/drivers/net/wireless/marvell/mwifiex/scan.c
>> @@ -32,7 +32,7 @@
>> #define WILDCARD_SSID_TLV_MAX_SIZE \
>> (MWIFIEX_MAX_SSID_LIST_LENGTH * \
>> (sizeof(struct mwifiex_ie_types_wildcard_ssid_params) \
>> - + IEEE80211_MAX_SSID_LEN))
>> + + IEEE80211_MAX_SSID_LEN + 1))
>>
>> /* Maximum memory needed for a mwifiex_scan_cmd_config with all TLVs at max */
>> #define MAX_SCAN_CFG_ALLOC (sizeof(struct mwifiex_scan_cmd_config) \
>>
>> base-commit: 4f3e012d4cfd1d9bf837870c961f462ca9f23ebe
>
^ permalink raw reply [flat|nested] 6+ messages in thread
* Re: [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan()
2024-09-17 15:08 [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan() Alper Nebi Yasak
2024-09-17 16:30 ` Andy Shevchenko
2024-09-17 18:10 ` Jeff Johnson
@ 2024-10-04 23:24 ` Brian Norris
2 siblings, 0 replies; 6+ messages in thread
From: Brian Norris @ 2024-10-04 23:24 UTC (permalink / raw)
To: Alper Nebi Yasak
Cc: linux-wireless, linux-kernel, David Lin, Dmitry Antipov,
Kalle Valo, Francesco Dolcini, Sascha Hauer, Kees Cook,
Gustavo A . R . Silva, Andy Shevchenko, Johannes Berg
On Tue, Sep 17, 2024 at 06:08:41PM +0300, Alper Nebi Yasak wrote:
> Replace one-element array with a flexible-array member in `struct
> mwifiex_ie_types_wildcard_ssid_params` to fix the following warning
> on a MT8173 Chromebook (mt8173-elm-hana):
>
> [ 356.775250] ------------[ cut here ]------------
> [ 356.784543] memcpy: detected field-spanning write (size 6) of single field "wildcard_ssid_tlv->ssid" at drivers/net/wireless/marvell/mwifiex/scan.c:904 (size 1)
> [ 356.813403] WARNING: CPU: 3 PID: 742 at drivers/net/wireless/marvell/mwifiex/scan.c:904 mwifiex_scan_networks+0x4fc/0xf28 [mwifiex]
>
> The "(size 6)" above is exactly the length of the SSID of the network
> this device was connected to. The source of the warning looks like:
>
> ssid_len = user_scan_in->ssid_list[i].ssid_len;
> [...]
> memcpy(wildcard_ssid_tlv->ssid,
> user_scan_in->ssid_list[i].ssid, ssid_len);
>
> Also adjust a #define that uses sizeof() on this struct to keep the
> value same as before.
>
> Signed-off-by: Alper Nebi Yasak <alpernebiyasak@gmail.com>
> ---
> I found these relevant patches that modify other such arrays, where the
> second one removes a -1 from some sizeof() calculation:
>
> https://lore.kernel.org/lkml/Y9xkECG3uTZ6T1dN@work/T/#u
> https://lore.kernel.org/lkml/ZsZa5xRcsLq9D+RX@elsanto/T/#u
>
> So I think we need the +1 to keep things same. But it appears to work
> fine without it, so I'm not sure. Maybe it should've had a -1 before
> that I would remove with this?
Thanks for the investigation and patch! I believe I agree with the other
comments, that then "+ 1" isn't necessary. It's just a wasteful extra
byte of allocation. Can you send a v2? (Bonus: with the suggested Fixes
tag. Double bonus if you test KASAN with __counted_by, for a second
patch.)
Thanks,
Brian
^ permalink raw reply [flat|nested] 6+ messages in thread
end of thread, other threads:[~2024-10-04 23:24 UTC | newest]
Thread overview: 6+ messages (download: mbox.gz follow: Atom feed
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2024-09-17 15:08 [PATCH] wifi: mwifiex: Fix memcpy() field-spanning write warning in mwifiex_config_scan() Alper Nebi Yasak
2024-09-17 16:30 ` Andy Shevchenko
2024-09-17 17:01 ` Dmitry Antipov
2024-09-17 18:10 ` Jeff Johnson
2024-09-17 18:21 ` Gustavo A. R. Silva
2024-10-04 23:24 ` Brian Norris
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