mwifiex_search_oui_in_ie() reads a pairwise-cipher (PTK) count from a beacon/probe-response RSN or WPA information element and then walks that many 4-byte OUIs, comparing each with memcmp(). The count comes straight from the (attacker-supplied) IE and is never checked against the element's own length, and the callers admit the element on element_id alone (has_ieee_hdr() / has_vendor_hdr(), no length check). A crafted RSN/WPA IE with a large pairwise count therefore makes the walk read up to 255 * 4 bytes past the element -- an out-of-bounds read of the kmemdup()'d beacon buffer, reachable from any AP whose beacon/probe response is processed during scan-result parsing. Pass the number of IE bytes available at the OUI list and bound the walk to the element. Keep the length signed and reject a negative value before any unsigned arithmetic, so a small or zero IE length cannot underflow to a large size_t and defeat the bound. Found by 0sec automated security-research tooling (https://0sec.ai). Fixes: 5e6e3a92b9a4 ("wireless: mwifiex: initial commit for Marvell mwifiex driver") Cc: stable@vger.kernel.org Assisted-by: 0sec:multi-model Signed-off-by: Doruk Tan Ozturk --- Changes in v3 (per Brian Norris's review of v2): - Keep ie_len signed and explicitly reject a negative (underflowed) length before any unsigned arithmetic. The v2 bound added the count to the offset and compared against (size_t)ie_len, so a small or zero IE length that underflowed ie_len wrapped to a large size_t and the bound would not fire. Changes in v2 (per Francesco Dolcini's review of v1): - Store offsetof(struct ie_body, ptk_body) in a named variable (ptk_body_offset) and reuse it in both bounds checks; no functional change. - Switch the Assisted-by trailer to 0sec:multi-model. drivers/net/wireless/marvell/mwifiex/scan.c | 25 ++++++++++++++++++--- 1 file changed, 22 insertions(+), 3 deletions(-) diff --git a/drivers/net/wireless/marvell/mwifiex/scan.c b/drivers/net/wireless/marvell/mwifiex/scan.c index 97c0ec3b822e7..473f4623ea199 100644 --- a/drivers/net/wireless/marvell/mwifiex/scan.c +++ b/drivers/net/wireless/marvell/mwifiex/scan.c @@ -104,12 +104,24 @@ has_vendor_hdr(struct ieee_types_vendor_specific *ie, u8 key) * a given oui in PTK. */ static u8 -mwifiex_search_oui_in_ie(struct ie_body *iebody, u8 *oui) +mwifiex_search_oui_in_ie(struct ie_body *iebody, u8 *oui, int ie_len) { + const size_t ptk_body_offset = offsetof(struct ie_body, ptk_body); u8 count; + /* ie_len is the number of bytes available at iebody. Keep it signed + * and reject a negative (underflowed) length before the unsigned + * comparisons below, so a small or zero IE length cannot wrap. + */ + if (ie_len < 0 || (size_t)ie_len < ptk_body_offset) + return MWIFIEX_OUI_NOT_PRESENT; + count = iebody->ptk_cnt[0]; + /* Reject an OUI count whose list would run past the element. */ + if (ptk_body_offset + count * sizeof(iebody->ptk_body) > (size_t)ie_len) + return MWIFIEX_OUI_NOT_PRESENT; + /* There could be multiple OUIs for PTK hence 1) Take the length. 2) Check all the OUIs for AES. @@ -143,11 +155,14 @@ mwifiex_is_rsn_oui_present(struct mwifiex_bssdescriptor *bss_desc, u32 cipher) u8 ret = MWIFIEX_OUI_NOT_PRESENT; if (has_ieee_hdr(bss_desc->bcn_rsn_ie, WLAN_EID_RSN)) { + int ie_len = (int)bss_desc->bcn_rsn_ie->ieee_hdr.len - + RSN_GTK_OUI_OFFSET; + iebody = (struct ie_body *) (((u8 *) bss_desc->bcn_rsn_ie->data) + RSN_GTK_OUI_OFFSET); oui = &mwifiex_rsn_oui[cipher][0]; - ret = mwifiex_search_oui_in_ie(iebody, oui); + ret = mwifiex_search_oui_in_ie(iebody, oui, ie_len); if (ret) return ret; } @@ -169,10 +184,14 @@ mwifiex_is_wpa_oui_present(struct mwifiex_bssdescriptor *bss_desc, u32 cipher) u8 ret = MWIFIEX_OUI_NOT_PRESENT; if (has_vendor_hdr(bss_desc->bcn_wpa_ie, WLAN_EID_VENDOR_SPECIFIC)) { + int ie_len = (int)bss_desc->bcn_wpa_ie->vend_hdr.len - + (int)sizeof(bss_desc->bcn_wpa_ie->vend_hdr.oui) - + WPA_GTK_OUI_OFFSET; + iebody = (struct ie_body *)((u8 *)bss_desc->bcn_wpa_ie->data + WPA_GTK_OUI_OFFSET); oui = &mwifiex_wpa_oui[cipher][0]; - ret = mwifiex_search_oui_in_ie(iebody, oui); + ret = mwifiex_search_oui_in_ie(iebody, oui, ie_len); if (ret) return ret; } -- 2.43.0