Coverity: wilc_parse_join_bss_param(): Memory - illegal accesses

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Hello!

This is an experimental automated report about issues detected by Coverity from a scan of next-20191031 as part of the linux-next weekly scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified lines of code (noted below) that were touched by recent commits:

4e0b0f42c9c7 ("staging: wilc1000: use struct to pack join parameters for FW")

Coverity reported the following:

*** CID 1487400: Memory - illegal accesses (OVERRUN) /drivers/staging/wilc1000/wilc_hif.c: 496 in wilc_parse_join_bss_param()

490     	if (supp_rates_ie) {
491     		if (supp_rates_ie[1] > (WILC_MAX_RATES_SUPPORTED - rates_len))
492     			param->supp_rates[0] = WILC_MAX_RATES_SUPPORTED;
493     		else
494     			param->supp_rates[0] += supp_rates_ie[1];
495
vvv     CID 1487400:  Memory - illegal accesses  (OVERRUN)
vvv     Overrunning array of 13 bytes at byte offset 13 by dereferencing pointer "&param->supp_rates[rates_len + 1]". [Note: The source code implementation of the function has been overridden by a builtin model.]
496     		memcpy(&param->supp_rates[rates_len + 1], supp_rates_ie + 2,
497     		       (param->supp_rates[0] - rates_len));

498 }
499
500 ht_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY, ies->data, ies->len);
501 if (ht_ie)

If this is a false positive, please let us know so we can mark it as such, or teach the Coverity rules to be smarter. If not, please make sure fixes get into linux-next. :) For patches fixing this, please include these lines (but double-check the "Fixes" first):

Reported-by coverity-bot <[email protected]>

Addresses-Coverity-ID: 1487400 ("Memory - illegal accesses")

Fixes 4e0b0f42c9c7 ("staging: wilc1000: use struct to pack join parameters for FW")

Thanks for your attention!

Quoted 18 lines · coverity-bot

External E-Mail

Hello!

This is an experimental automated report about issues detected by Coverity from a scan of next-20191031 as part of the linux-next weekly scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified lines of code (noted below) that were touched by recent commits:

4e0b0f42c9c7 ("staging: wilc1000: use struct to pack join parameters for FW")

Coverity reported the following:

*** CID 1487400: Memory - illegal accesses (OVERRUN) /drivers/staging/wilc1000/wilc_hif.c: 496 in wilc_parse_join_bss_param()

Quoted 10 lines

490     	if (supp_rates_ie) {
491     		if (supp_rates_ie[1] > (WILC_MAX_RATES_SUPPORTED - rates_len))
492     			param->supp_rates[0] = WILC_MAX_RATES_SUPPORTED;
493     		else
494     			param->supp_rates[0] += supp_rates_ie[1];
495
vvv     CID 1487400:  Memory - illegal accesses  (OVERRUN)
vvv     Overrunning array of 13 bytes at byte offset 13 by dereferencing pointer "&param->supp_rates[rates_len + 1]". [Note: The source code implementation of the function has been overridden by a builtin model.]
496     		memcpy(&param->supp_rates[rates_len + 1], supp_rates_ie + 2,
497     		       (param->supp_rates[0] - rates_len));

As I understand, Ideally this condition should never arise because the maximum number of supported *basic rates* is up to 8 so the value of ‘rate_len’ will always be less then WILC_MAX_RATES_SUPPPRTED (i.e 12). Therefore '&param->supp_rates[rates_len+ 1]' will never try to access the 13 bytes in the array.
But for the safer side, if need I can create a patch to block the addition of extended supported rates in ‘param->supp_rates’ array if ‘rates_len’ is 12 (i.e 'param->supp_rates' array is full after filing the basic supported rates).

Quoted 18 lines

498 }
499
500 ht_ie = cfg80211_find_ie(WLAN_EID_HT_CAPABILITY, ies->data, ies->len);
501 if (ht_ie)

If this is a false positive, please let us know so we can mark it as such, or teach the Coverity rules to be smarter. If not, please make sure fixes get into linux-next. :) For patches fixing this, please include these lines (but double-check the "Fixes" first):

Reported-by coverity-bot <[email protected]>

Addresses-Coverity-ID: 1487400 ("Memory - illegal accesses")

Fixes 4e0b0f42c9c7 ("staging: wilc1000: use struct to pack join parameters for FW")

Thanks for your attention!

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Quoted 32 lines · On Tue, Nov 05, 2019 at 06:11:03AM +0000, [email protected] wrote:

Quoted 18 lines · coverity-bot

External E-Mail

Hello!

This is an experimental automated report about issues detected by Coverity from a scan of next-20191031 as part of the linux-next weekly scan project:
https://scan.coverity.com/projects/linux-next-weekly-scan

You're getting this email because you were associated with the identified lines of code (noted below) that were touched by recent commits:

4e0b0f42c9c7 ("staging: wilc1000: use struct to pack join parameters for FW")

Coverity reported the following:

*** CID 1487400: Memory - illegal accesses (OVERRUN) /drivers/staging/wilc1000/wilc_hif.c: 496 in wilc_parse_join_bss_param()

Quoted 10 lines

490     	if (supp_rates_ie) {
491     		if (supp_rates_ie[1] > (WILC_MAX_RATES_SUPPORTED - rates_len))
492     			param->supp_rates[0] = WILC_MAX_RATES_SUPPORTED;
493     		else
494     			param->supp_rates[0] += supp_rates_ie[1];
495
vvv     CID 1487400:  Memory - illegal accesses  (OVERRUN)
vvv     Overrunning array of 13 bytes at byte offset 13 by dereferencing pointer "&param->supp_rates[rates_len + 1]". [Note: The source code implementation of the function has been overridden by a builtin model.]
496     		memcpy(&param->supp_rates[rates_len + 1], supp_rates_ie + 2,
497     		       (param->supp_rates[0] - rates_len));

Quoted 9 lines

As I understand, Ideally this condition should never arise because the maximum number of supported *basic rates* is up to 8 so the value of ‘rate_len’ will always be less then WILC_MAX_RATES_SUPPPRTED (i.e 12). Therefore '&param->supp_rates[rates_len+ 1]' will never try to access the 13 bytes in the array.
But for the safer side, if need I can create a patch to block the addition of extended supported rates in ‘param->supp_rates’ array if ‘rates_len’ is 12 (i.e 'param->supp_rates' array is full after filing the basic supported rates).

I don't know the code myself, but generally speaking, it's best to validate any assumptions like this. I'd say add a patch for it, since it sounds pretty straight-forward to test.