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[162.197.212.70]) by smtp.gmail.com with ESMTPSA id a92af1059eb24-13b3c7ef188sm13001922c88.2.2026.07.02.16.09.23 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 02 Jul 2026 16:09:24 -0700 (PDT) Message-ID: <3fd92e0979538d5b36fdfb37d30583268b6fbf74.camel@dubeyko.com> Subject: Re: [PATCH] nilfs2: reject invalid block index in GC ioctl From: Viacheslav Dubeyko To: Ryusuke Konishi Cc: linux-nilfs , LKML , syzbot+c37bed40868932d790e9@syzkaller.appspotmail.com, syzkaller-bugs@googlegroups.com, wuyankun Date: Thu, 02 Jul 2026 16:09:22 -0700 In-Reply-To: <20260702161045.27555-1-konishi.ryusuke@gmail.com> References: <20260702161045.27555-1-konishi.ryusuke@gmail.com> Autocrypt: addr=slava@dubeyko.com; prefer-encrypt=mutual; keydata=mQINBGgaTLYBEADaJc/WqWTeunGetXyyGJ5Za7b23M/ozuDCWCp+yWUa2GqQKH40dxRIR zshgOmAue7t9RQJU9lxZ4ZHWbi1Hzz85+0omefEdAKFmxTO6+CYV0g/sapU0wPJws3sC2Pbda9/eJ ZcvScAX2n/PlhpTnzJKf3JkHh3nM1ACO3jzSe2/muSQJvqMLG2D71ccekr1RyUh8V+OZdrPtfkDam V6GOT6IvyE+d+55fzmo20nJKecvbyvdikWwZvjjCENsG9qOf3TcCJ9DDYwjyYe1To8b+mQM9nHcxp jUsUuH074BhISFwt99/htZdSgp4csiGeXr8f9BEotRB6+kjMBHaiJ6B7BIlDmlffyR4f3oR/5hxgy dvIxMocqyc03xVyM6tA4ZrshKkwDgZIFEKkx37ec22ZJczNwGywKQW2TGXUTZVbdooiG4tXbRBLxe ga/NTZ52ZdEkSxAUGw/l0y0InTtdDIWvfUT+WXtQcEPRBE6HHhoeFehLzWL/o7w5Hog+0hXhNjqte fzKpI2fWmYzoIb6ueNmE/8sP9fWXo6Av9m8B5hRvF/hVWfEysr/2LSqN+xjt9NEbg8WNRMLy/Y0MS p5fgf9pmGF78waFiBvgZIQNuQnHrM+0BmYOhR0JKoHjt7r5wLyNiKFc8b7xXndyCDYfniO3ljbr0j tXWRGxx4to6FwARAQABtCZWaWFjaGVzbGF2IER1YmV5a28gPHNsYXZhQGR1YmV5a28uY29tPokCVw QTAQoAQQIbAQUJA8JnAAULCQgHAgYVCgkICwIEFgIDAQIeAQIXgBYhBFXDC2tnzsoLQtrbBDlc2cL fhEB1BQJoGl5PAhkBAAoJEDlc2cLfhEB17DsP/jy/Dx19MtxWOniPqpQf2s65enkDZuMIQ94jSg7B F2qTKIbNR9SmsczjyjC+/J7m7WZRmcqnwFYMOyNfh12aF2WhjT7p5xEAbvfGVYwUpUrg/lcacdT0D Yk61GGc5ZB89OAWHLr0FJjI54bd7kn7E/JRQF4dqNsxU8qcPXQ0wLHxTHUPZu/w5Zu/cO+lQ3H0Pj pSEGaTAh+tBYGSvQ4YPYBcV8+qjTxzeNwkw4ARza8EjTwWKP2jWAfA/ay4VobRfqNQ2zLoo84qDtN Uxe0zPE2wobIXELWkbuW/6hoQFPpMlJWz+mbvVms57NAA1HO8F5c1SLFaJ6dN0AQbxrHi45/cQXla 9hSEOJjxcEnJG/ZmcomYHFneM9K1p1K6HcGajiY2BFWkVet9vuHygkLWXVYZ0lr1paLFR52S7T+cf 6dkxOqu1ZiRegvFoyzBUzlLh/elgp3tWUfG2VmJD3lGpB3m5ZhwQ3rFpK8A7cKzgKjwPp61Me0o9z HX53THoG+QG+o0nnIKK7M8+coToTSyznYoq9C3eKeM/J97x9+h9tbizaeUQvWzQOgG8myUJ5u5Dr4 6tv9KXrOJy0iy/dcyreMYV5lwODaFfOeA4Lbnn5vRn9OjuMg1PFhCi3yMI4lA4umXFw0V2/OI5rgW BQELhfvW6mxkihkl6KLZX8m1zcHitCpWaWFjaGVzbGF2IER1YmV5a28gPFNsYXZhLkR1YmV5a29Aa WJtLmNvbT6JAlQEEwEKAD4WIQRVwwtrZ87KC0La2wQ5XNnC34RAdQUCaBpd7AIbAQUJA8JnAAULCQ gHAgYVCgkICwIEFgIDAQIeAQIXgAAKCRA5XNnC34RAdYjFEACiWBEybMt1xjRbEgaZ3UP5i2bSway DwYDvgWW5EbRP7JcqOcZ2vkJwrK3gsqC3FKpjOPh7ecE0I4vrabH1Qobe2N8B2Y396z24mGnkTBbb 16Uz3PC93nFN1BA0wuOjlr1/oOTy5gBY563vybhnXPfSEUcXRd28jI7z8tRyzXh2tL8ZLdv1u4vQ8 E0O7lVJ55p9yGxbwgb5vXU4T2irqRKLxRvU80rZIXoEM7zLf5r7RaRxgwjTKdu6rYMUOfoyEQQZTD 4Xg9YE/X8pZzcbYFs4IlscyK6cXU0pjwr2ssjearOLLDJ7ygvfOiOuCZL+6zHRunLwq2JH/RmwuLV mWWSbgosZD6c5+wu6DxV15y7zZaR3NFPOR5ErpCFUorKzBO1nA4dwOAbNym9OGkhRgLAyxwpea0V0 ZlStfp0kfVaSZYo7PXd8Bbtyjali0niBjPpEVZdgtVUpBlPr97jBYZ+L5GF3hd6WJFbEYgj+5Af7C UjbX9DHweGQ/tdXWRnJHRzorxzjOS3003ddRnPtQDDN3Z/XzdAZwQAs0RqqXrTeeJrLppFUbAP+HZ TyOLVJcAAlVQROoq8PbM3ZKIaOygjj6Yw0emJi1D9OsN2UKjoe4W185vamFWX4Ba41jmCPrYJWAWH fAMjjkInIPg7RLGs8FiwxfcpkILP0YbVWHiNAabQoVmlhY2hlc2xhdiBEdWJleWtvIDx2ZHViZXlr b0BrZXJuZWwub3JnPokCVAQTAQoAPhYhBFXDC2tnzsoLQtrbBDlc2cLfhEB1BQJoVemuAhsBBQkDw mcABQsJCAcCBhUKCQgLAgQWAgMBAh4BAheAAAoJEDlc2cLfhEB1GRwP/1scX5HO9Sk7dRicLD/fxo ipwEs+UbeA0/TM8OQfdRI4C/tFBYbQCR7lD05dfq8VsYLEyrgeLqP/iRhabLky8LTaEdwoAqPDc/O 9HRffx/faJZqkKc1dZryjqS6b8NExhKOVWmDqN357+Cl/H4hT9wnvjCj1YEqXIxSd/2Pc8+yw/KRC AP7jtRzXHcc/49Lpz/NU5irScusxy2GLKa5o/13jFK3F1fWX1wsOJF8NlTx3rLtBy4GWHITwkBmu8 zI4qcJGp7eudI0l4xmIKKQWanEhVdzBm5UnfyLIa7gQ2T48UbxJlWnMhLxMPrxgtC4Kos1G3zovEy Ep+fJN7D1pwN9aR36jVKvRsX7V4leIDWGzCdfw1FGWkMUfrRwgIl6i3wgqcCP6r9YSWVQYXdmwdMu 1RFLC44iF9340S0hw9+30yGP8TWwd1mm8V/+zsdDAFAoAwisi5QLLkQnEsJSgLzJ9daAsE8KjMthv hUWHdpiUSjyCpigT+KPl9YunZhyrC1jZXERCDPCQVYgaPt+Xbhdjcem/ykv8UVIDAGVXjuk4OW8la nf8SP+uxkTTDKcPHOa5rYRaeNj7T/NClRSd4z6aV3F6pKEJnEGvv/DFMXtSHlbylhyiGKN2Amd0b4 9jg+DW85oNN7q2UYzYuPwkHsFFq5iyF1QggiwYYTpoVXsw Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: quoted-printable User-Agent: Evolution 3.60.1 (by Flathub.org) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 On Fri, 2026-07-03 at 01:07 +0900, Ryusuke Konishi wrote: > Syzbot reported list corruption caused by a double list_add_tail() > call on > bh->b_assoc_buffers within nilfs_lookup_dirty_data_buffers(). >=20 > Analysis revealed that the root cause was the insertion of a > page/folio > with a page index of ULONG_MAX into the page cache via the GC ioctl. > filemap_get_folios_tag(), called by > nilfs_lookup_dirty_data_buffers(), > repeatedly detects a dirty folio with a page index of ULONG_MAX due > to > index wrap-around, leading to duplicate processing of dirty buffers. >=20 > As a preparatory step, the GC ioctl loads the page/folio of the block > to > be moved during GC and inserts it into the page cache based on > information > in the nilfs_vdesc structure passed as an argument.=C2=A0 Normally, this > does > not cause issues because the user-space GC library configures the > nilfs_vdesc structure properly.=C2=A0 However, since there is no range > check on > the parameters determining the page index, a request with > artificially > crafted parameters -- such as those generated by Syzbot -- can result > in a > page/folio being inserted with a page index of ULONG_MAX, triggering > the > above problem. >=20 > This resolves the issue by checking the ranges of 'vd_offset' and > 'vd_vblocknr' in the nilfs_vdesc structure that determine the page > index, > thereby preventing the invalid page/folio insertions. >=20 > Reported-by: syzbot+c37bed40868932d790e9@syzkaller.appspotmail.com > Closes: https://syzkaller.appspot.com/bug?extid=3Dc37bed40868932d790e9 > Fixes: 7942b919f732 ("nilfs2: ioctl operations") > Cc: wuyankun > Cc: stable@vger.kernel.org > Signed-off-by: Ryusuke Konishi > --- > Hi Viacheslav, >=20 > Please apply this one. >=20 > This fixes the list corruption issue recently detected by syzbot, > that > can occur when out-of-range values are intentionally passed to > certain > GC ioctl parameters. >=20 > Thanks, > Ryusuke Konishi >=20 > =C2=A0fs/nilfs2/ioctl.c | 20 ++++++++++++++++++-- > =C2=A01 file changed, 18 insertions(+), 2 deletions(-) >=20 > diff --git a/fs/nilfs2/ioctl.c b/fs/nilfs2/ioctl.c > index b73f2c5d10f0..0957316e58b8 100644 > --- a/fs/nilfs2/ioctl.c > +++ b/fs/nilfs2/ioctl.c > @@ -527,6 +527,7 @@ static int nilfs_ioctl_get_bdescs(struct inode > *inode, struct file *filp, > =C2=A0 * Return: 0 on success, or one of the following negative error > codes on > =C2=A0 * failure: > =C2=A0 * * %-EEXIST - Block conflict detected. > + * * %-EINVAL - Invalid virtual block descriptor. > =C2=A0 * * %-EIO - I/O error. > =C2=A0 * * %-ENOENT - Requested block doesn't exist. > =C2=A0 * * %-ENOMEM - Insufficient memory available. > @@ -536,15 +537,30 @@ static int nilfs_ioctl_move_inode_block(struct > inode *inode, > =C2=A0 struct list_head *buffers) > =C2=A0{ > =C2=A0 struct buffer_head *bh; > + __u64 limit_blkidx =3D (__u64)inode->i_sb->s_maxbytes >> > inode->i_blkbits; > =C2=A0 int ret; > =C2=A0 > - if (vdesc->vd_flags =3D=3D 0) > + /* > + * vblocknr 0 is reserved as an invalid pointer.=C2=A0 Also, > limit_blkidx > + * ensures that the page index converted from vd_vblocknr > never > + * overflows the page cache limit and respects the > architecture's bmap > + * key width. > + */ > + if (unlikely(vdesc->vd_vblocknr =3D=3D 0 || > + vdesc->vd_vblocknr >=3D limit_blkidx)) > + return -EINVAL; > + > + if (vdesc->vd_flags =3D=3D 0) { > + if (unlikely(vdesc->vd_offset >=3D limit_blkidx)) > + return -EINVAL; > + > =C2=A0 ret =3D nilfs_gccache_submit_read_data( > =C2=A0 inode, vdesc->vd_offset, vdesc->vd_blocknr, > =C2=A0 vdesc->vd_vblocknr, &bh); > - else > + } else { > =C2=A0 ret =3D nilfs_gccache_submit_read_node( > =C2=A0 inode, vdesc->vd_blocknr, vdesc- > >vd_vblocknr, &bh); > + } > =C2=A0 > =C2=A0 if (unlikely(ret < 0)) { > =C2=A0 if (ret =3D=3D -ENOENT) Applied. Thanks, Slava.