On Fri, Dec 02, 2022 at 11:42:36PM +0000, Ryder Lee wrote: > On Fri, 2022-12-02 at 15:04 -0800, Kees Cook wrote: > > > > > On Fri, Dec 02, 2022 at 10:56:19PM +0000, Ryder Lee wrote: > > > On Fri, 2022-12-02 at 14:24 -0800, coverity-bot wrote: > > > > Hello! > > > > > > > > This is an experimental semi-automated report about issues > > > > detected > > > > by > > > > Coverity from a scan of next-20221202 as part of the linux-next > > > > scan > > > > project: > > > > > > > > > > > https://urldefense.com/v3/__https://scan.coverity.com/projects/linux-next-weekly-scan__;!!CTRNKA9wMg0ARbw!j7j_C0KpO4VD2yMOodvpeIexTGq4fhy2yq6nokNua9u4LToiUOLk4ou8JFFNrXkrh80d5BK2k44faRQstHE9$ > > > > > > > > > > > > > > > You're getting this email because you were associated with the > > > > identified > > > > lines of code (noted below) that were touched by commits: > > > > > > > > Thu Feb 3 13:57:56 2022 +0100 > > > > 417a4534d223 ("mt76: mt7915: update mt7915_chan_mib_offs for > > > > mt7916") > > > > > > > > Coverity reported the following: > > > > > > > > *** CID 1527801: Memory - illegal accesses (OVERRUN) > > > > drivers/net/wireless/mediatek/mt76/mt7915/mcu.c:3005 in > > > > mt7915_mcu_get_chan_mib_info() > > > > 2999 start = 5; > > > > 3000 ofs = 0; > > > > 3001 } > > > > 3002 > > > > 3003 for (i = 0; i < 5; i++) { > > > > 3004 req[i].band = cpu_to_le32(phy->mt76->band_idx); > > > > vvv CID 1527801: Memory - illegal accesses (OVERRUN) > > > > vvv Overrunning array "offs" of 9 4-byte elements at element > > > > index 9 (byte offset 39) using index "i + start" (which evaluates > > > > to > > > > 9). > > > > 3005 req[i].offs = cpu_to_le32(offs[i + start]); > > > > 3006 > > > > 3007 if (!is_mt7915(&dev->mt76) && i == 3) > > > > 3008 break; > > > > 3009 } > > > > 3010 > > > > > > > > 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): > > > > > > > > > > I think this is a false postive as the subsequent check 'if > > > (!is_mt7915(&dev->mt76) && i == 3)' should break array "offs" of 8. > > > > Ah, okay. What if is_mt7915(&dev->mt76) is always true? > > > > -Kees > > int start = 0; > > if (!is_mt7915(&dev->mt76)) { > start = 5; > ofs = 0; > } > > for (i = 0; i < 5; i++) { > req[i].band = cpu_to_le32(phy->band_idx); > req[i].offs = cpu_to_le32(offs[i + start]); > > if (!is_mt7915(&dev->mt76) && i == 3) // > break; > } > > For 'is_mt7915' case, start:0 and i: 0 1 2 3 4, whereas !is_mt7915' > case, start:5 and i: 0 1 2 3 (then break). > > I know it's a bit tricky. This is used to differentiate chipset > revision. Ah-ha! Gotcha now. Thanks for the details and sorry for the noise! :) -Kees -- Kees Cook
