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Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Breno Leitao CC: , , Karina Yankevich , References: <20240812084312.14127-1-r.smirnov@omp.ru> Organization: Open Mobile Platform Message-ID: <61528e45-b2a7-5ef9-09dd-9cdc63c4599e@omp.ru> Date: Mon, 12 Aug 2024 12:41:03 +0300 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.10.1 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 In-Reply-To: <20240812084312.14127-1-r.smirnov@omp.ru> Content-Type: text/plain; charset="utf-8" Content-Language: en-US Content-Transfer-Encoding: 7bit X-ClientProxiedBy: msexch01.omp.ru (10.188.4.12) To msexch01.omp.ru (10.188.4.12) X-KSE-ServerInfo: msexch01.omp.ru, 9 X-KSE-AntiSpam-Interceptor-Info: scan successful X-KSE-AntiSpam-Version: 6.1.0, Database issued on: 08/12/2024 09:25:26 X-KSE-AntiSpam-Status: KAS_STATUS_NOT_DETECTED X-KSE-AntiSpam-Method: none X-KSE-AntiSpam-Rate: 59 X-KSE-AntiSpam-Info: Lua profiles 186993 [Aug 12 2024] X-KSE-AntiSpam-Info: Version: 6.1.0.4 X-KSE-AntiSpam-Info: Envelope from: s.shtylyov@omp.ru X-KSE-AntiSpam-Info: LuaCore: 24 0.3.24 186c4d603b899ccfd4883d230c53f273b80e467f X-KSE-AntiSpam-Info: {rep_avail} X-KSE-AntiSpam-Info: {relay has no DNS name} X-KSE-AntiSpam-Info: {SMTP from is not routable} X-KSE-AntiSpam-Info: {Found in DNSBL: 178.176.72.190 in (user) b.barracudacentral.org} X-KSE-AntiSpam-Info: omp.ru:7.1.1;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;127.0.0.199:7.1.2 X-KSE-AntiSpam-Info: ApMailHostAddress: 178.176.72.190 X-KSE-AntiSpam-Info: {DNS response errors} X-KSE-AntiSpam-Info: Rate: 59 X-KSE-AntiSpam-Info: Status: not_detected X-KSE-AntiSpam-Info: Method: none X-KSE-AntiSpam-Info: Auth:dmarc=temperror header.from=omp.ru;spf=temperror smtp.mailfrom=omp.ru;dkim=none X-KSE-Antiphishing-Info: Clean X-KSE-Antiphishing-ScanningType: Heuristic X-KSE-Antiphishing-Method: None X-KSE-Antiphishing-Bases: 08/12/2024 09:30:00 X-KSE-Antivirus-Interceptor-Info: scan successful X-KSE-Antivirus-Info: Clean, bases: 8/12/2024 4:43:00 AM X-KSE-Attachment-Filter-Triggered-Rules: Clean X-KSE-Attachment-Filter-Triggered-Filters: Clean X-KSE-BulkMessagesFiltering-Scan-Result: InTheLimit Hello! Failed to notice an issue with the subject in the internal review; I think it should look like "net: ppp: bsd_comp: fix integer overflow in bsd_decompress()"... On 8/12/24 11:43 AM, Roman Smirnov wrote: > The result of a bit shift has type int. So far, so good... :-) > If ibuf is greater than or *ibuf maybe? :-) > equal to 128, a sign switch will occur. I wonder whether you had looked at the .lsy file before writing that... Actually, movzvl (%rdi),%eax is used when reading *buf, so no sign extension occurs at this point... it occurs when casting the result of shift to *unsignjed long* > After that, the higher 32 bits in accm will be set to 1. Only if we have 1 in the bit 31 after shl %cl,%eax... > Cast the result of the expression to unsigned long. I strongly suspect we should re-declare accm as *unsigned int* instead... > Found by Linux Verification Center (linuxtesting.org) with Svace. > > Signed-off-by: Roman Smirnov > --- > drivers/net/ppp/bsd_comp.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/drivers/net/ppp/bsd_comp.c b/drivers/net/ppp/bsd_comp.c > index 55954594e157..078fe8c9bee8 100644 > --- a/drivers/net/ppp/bsd_comp.c > +++ b/drivers/net/ppp/bsd_comp.c > @@ -918,7 +918,7 @@ static int bsd_decompress (void *state, unsigned char *ibuf, int isize, > */ > > bitno -= 8; > - accm |= *ibuf++ << bitno; > + accm |= (unsigned long)(*ibuf++) << bitno; > if (tgtbitno < bitno) > { > continue; > MBR, Sergey