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ext4: don't fail GETFSUUID when the caller provides a long buffer
commit a7e9d977e0
upstream.
If userspace provides a longer UUID buffer than is required, we
shouldn't fail the call with EINVAL -- rather, we can fill the caller's
buffer with the bytes we /can/ fill, and update the length field to
reflect what we copied. This doesn't break the UAPI since we're
enabling a case that currently fails, and so far Ted hasn't released a
version of e2fsprogs that uses the new ext4 ioctl.
Signed-off-by: Darrick J. Wong <djwong@kernel.org>
Reviewed-by: Catherine Hoang <catherine.hoang@oracle.com>
Link: https://lore.kernel.org/r/166811139478.327006.13879198441587445544.stgit@magnolia
Signed-off-by: Theodore Ts'o <tytso@mit.edu>
Cc: stable@kernel.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
parent
13271fbbe8
commit
b753b0be45
1 changed files with 4 additions and 2 deletions
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@ -1159,14 +1159,16 @@ static int ext4_ioctl_getuuid(struct ext4_sb_info *sbi,
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return -EINVAL;
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}
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if (fsuuid.fsu_len != UUID_SIZE || fsuuid.fsu_flags != 0)
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if (fsuuid.fsu_len < UUID_SIZE || fsuuid.fsu_flags != 0)
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return -EINVAL;
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lock_buffer(sbi->s_sbh);
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memcpy(uuid, sbi->s_es->s_uuid, UUID_SIZE);
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unlock_buffer(sbi->s_sbh);
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if (copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE))
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fsuuid.fsu_len = UUID_SIZE;
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if (copy_to_user(ufsuuid, &fsuuid, sizeof(fsuuid)) ||
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copy_to_user(&ufsuuid->fsu_uuid[0], uuid, UUID_SIZE))
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return -EFAULT;
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return 0;
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}
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