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Miller" , linux-crypto@vger.kernel.org, linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable Message-Id: References: <20260826103744.1554131-1-Jeremy.Jean@oss.cyber.gouv.fr> <20260826103744.1554131-2-Jeremy.Jean@oss.cyber.gouv.fr> To: =?utf-8?B?SsOpcsOpbXkgSmVhbg==?= X-Mailer: Apple Mail (2.3864.700.51.1.1) X-TM-AS-GCONF: 00 X-Proofpoint-ORIG-GUID: 9S5tsbgRv8wJc3Dg6MZZ3oPO72zQD1UU X-Proofpoint-Spam-Info: AW1haW4tMjYwODI2MDEyOSBTYWx0ZWRfX7ZldgjrWg2mY qDfZ8K5WJcJuV6B0hUCs1/U1SpQJP++0OIS63PKVcw8+3LPseCAHGzjFiUTN3BJAzJgRZ+2PsPY Ht5kpKTenrdHwNfSsl1sfQDszWWMda4= X-Proofpoint-GUID: 9S5tsbgRv8wJc3Dg6MZZ3oPO72zQD1UU X-Authority-Analysis: v=2.4 cv=JZyMa0KV c=1 sm=1 tr=0 ts=6a8f09d6 cx=c_pps a=bLidbwmWQ0KltjZqbj+ezA==:117 a=bLidbwmWQ0KltjZqbj+ezA==:17 a=IkcTkHD0fZMA:10 a=Sv0fKeRqtYgA:10 a=VkNPw1HP01LnGYTKEx00:22 a=RnoormkPH1_aCDwRdu11:22 a=U7nrCbtTmkRpXpFmAIza:22 a=VnNF1IyMAAAA:8 a=hsIq0pbpFFD4-NfFpr0A:9 a=QEXdDO2ut3YA:10 X-Proofpoint-Spam-Details-Enc: AW1haW4tMjYwODI2MDEyOSBTYWx0ZWRfX3ehDIXLkKmiN mKq2DpdvhIrudqGeZcKdtOeIhSSANChnLZtaBGskKUqOtzdIW2qA4RnddqhNi72Ms1d+vHFdxAu qMuJhcQVLI+kDYpSVjqWodyamEUK6vUpjoFSuqtCIAJBWwC6Tvtb5Mk+f2pl1shkXl7s6fMx9iH IJVWCimxbbZkB7BYMOf4o/UUxOEvDO4oFZssxvwps/tHXbZoYZxOe+BOfGLds5L7BZ/gLR+29PY aRNGVgBHmUCgIjq52vx16cF1rOzoMlPW16RAv1f4YBfjkdC6FOTdGV7HbK4NqKCRYWbmP6Wc5Ke 3il5GklWfMX1SJPhaKBCQrE43LCyE2PyjO2/zqO1XJb22gGCrEH8vv3yyW3qjTr8+jXhvxQolS6 57oZ2EAlzrc8qeRVOBTIrwep9B7bOXr9YYHY6f8LO0vI9FGxI7WXSglXf+cH8sIKIEFPS8vvBPv WOk+xWCxac4f0oEoyPA== X-Proofpoint-Virus-Version: vendor=baseguard engine=ICAP:2.0.293,Aquarius:18.0.1176,Hydra:6.1.134,FMLib:17.12.100.49 definitions=2026-08-26_04,2026-08-26_02,2025-10-01_01 X-Proofpoint-Spam-Details: rule=outbound_notspam policy=outbound score=0 spamscore=0 clxscore=1011 adultscore=0 priorityscore=1501 impostorscore=0 malwarescore=0 bulkscore=0 lowpriorityscore=0 suspectscore=0 phishscore=0 classifier=typeunknown authscore=0 authtc= authcc= route=outbound adjust=0 reason=mlx scancount=1 engine=8.22.0-2606150000 definitions=main-2608260129 > On 26 Aug 2026, at 4:07=E2=80=AFPM, J=C3=A9r=C3=A9my Jean = wrote: >=20 > rsassa_pkcs1_sign() subtracts 11 from the unsigned key size before > checking that the key is large enough for PKCS#1 v1.5 padding: >=20 > if (slen + hash_prefix->size > ctx->key_size - 11) > return -EOVERFLOW; >=20 > If the RSA modulus is shorter than 11 bytes, the subtraction wraps. > With a one-byte key and hash=3Dnone, the padding memset() writes past > the output buffer. >=20 > KASAN reports: >=20 > BUG: KASAN: slab-out-of-bounds in rsassa_pkcs1_sign+0x1ad/0x3b0 > Write of size 4294967294 at addr ... > The buggy address is located 0 bytes to the right of > allocated 1-byte region [...] >=20 > Reject keys shorter than the minimum encoded message size. >=20 > Fixes: 3d5b1ecdea6f ("crypto: rsa - RSA padding algorithm") > Assisted-by: Codex:gpt-5 > Signed-off-by: J=C3=A9r=C3=A9my Jean Reviewed-by: Sudhakar Kuppusamy Thanks, Sudhakar > --- > crypto/rsassa-pkcs1.c | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) >=20 > diff --git a/crypto/rsassa-pkcs1.c b/crypto/rsassa-pkcs1.c > index 94fa5e9600e7..d0e4a885397f 100644 > --- a/crypto/rsassa-pkcs1.c > +++ b/crypto/rsassa-pkcs1.c > @@ -169,7 +169,7 @@ static int rsassa_pkcs1_sign(struct crypto_sig = *tfm, > u8 *in_buf; > int err; >=20 > - if (!ctx->key_size) > + if (ctx->key_size < 11) > return -EINVAL; >=20 > if (dlen < ctx->key_size) > --=20 > 2.47.3 >=20 >=20