| Message ID | 20210925135533.20522-1-len.baker@gmx.com (mailing list archive) |
|---|---|
| State | Awaiting Upstream |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [v2] nl80211: prefer struct_size over open coded arithmetic | expand |
| Context | Check | Description |
|---|---|---|
| netdev/cover_letter | success | Link |
| netdev/fixes_present | success | Link |
| netdev/patch_count | success | Link |
| netdev/tree_selection | success | Guessed tree name to be net-next |
| netdev/subject_prefix | warning | Target tree name not specified in the subject |
| netdev/cc_maintainers | success | CCed 5 of 5 maintainers |
| netdev/source_inline | success | Was 0 now: 0 |
| netdev/verify_signedoff | success | Link |
| netdev/module_param | success | Was 0 now: 0 |
| netdev/build_32bit | success | Errors and warnings before: 0 this patch: 0 |
| netdev/kdoc | success | Errors and warnings before: 0 this patch: 0 |
| netdev/verify_fixes | success | Link |
| netdev/checkpatch | success | total: 0 errors, 0 warnings, 0 checks, 29 lines checked |
| netdev/build_allmodconfig_warn | success | Errors and warnings before: 0 this patch: 0 |
| netdev/header_inline | success | Link |
diff --git a/net/wireless/nl80211.c b/net/wireless/nl80211.c index bf7cd4752547..fa7ff61c5b07 100644 --- a/net/wireless/nl80211.c +++ b/net/wireless/nl80211.c @@ -11767,8 +11767,8 @@ static int nl80211_set_cqm_rssi(struct genl_info *info, if (n_thresholds) { struct cfg80211_cqm_config *cqm_config; - cqm_config = kzalloc(sizeof(struct cfg80211_cqm_config) + - n_thresholds * sizeof(s32), GFP_KERNEL); + cqm_config = kzalloc(struct_size(cqm_config, rssi_thresholds, + n_thresholds), GFP_KERNEL); if (!cqm_config) { err = -ENOMEM; goto unlock; @@ -11777,7 +11777,8 @@ static int nl80211_set_cqm_rssi(struct genl_info *info, cqm_config->rssi_hyst = hysteresis; cqm_config->n_rssi_thresholds = n_thresholds; memcpy(cqm_config->rssi_thresholds, thresholds, - n_thresholds * sizeof(s32)); + flex_array_size(cqm_config, rssi_thresholds, + n_thresholds)); wdev->cqm_config = cqm_config; } @@ -15081,9 +15082,7 @@ static int nl80211_set_sar_specs(struct sk_buff *skb, struct genl_info *info) if (specs > rdev->wiphy.sar_capa->num_freq_ranges) return -EINVAL; - sar_spec = kzalloc(sizeof(*sar_spec) + - specs * sizeof(struct cfg80211_sar_sub_specs), - GFP_KERNEL); + sar_spec = kzalloc(struct_size(sar_spec, sub_specs, specs), GFP_KERNEL); if (!sar_spec) return -ENOMEM;
As noted in the "Deprecated Interfaces, Language Features, Attributes, and Conventions" documentation [1], size calculations (especially multiplication) should not be performed in memory allocator (or similar) function arguments due to the risk of them overflowing. This could lead to values wrapping around and a smaller allocation being made than the caller was expecting. Using those allocations could lead to linear overflows of heap memory and other misbehaviors. So, use the struct_size() helper to do the arithmetic instead of the argument "size + count * size" in the kzalloc() functions. Also, take the opportunity to refactor the memcpy() call to use the flex_array_size() helper. This code was detected with the help of Coccinelle and audited and fixed manually. [1] https://www.kernel.org/doc/html/latest/process/deprecated.html#open-coded-arithmetic-in-allocator-arguments Signed-off-by: Len Baker <len.baker@gmx.com> --- Changelog v1 -> v2 - Rebase against v5.15-rc2 - Remove the unnecessary "size" variable (Gustavo A. R. Silva). - Update the commit changelog to inform that this code was detected using a Coccinelle script (Gustavo A. R. Silva). net/wireless/nl80211.c | 11 +++++------ 1 file changed, 5 insertions(+), 6 deletions(-) -- 2.25.1