Updates to UFS/FFS superblock integrity checks when reading a superblock.
Further updates based on ways Peter Holm found to corrupt UFS superblocks in ways that could cause kernel hangs or crashes. No legitimate superblocks should fail as a result of these changes. Reported by: Peter Holm Tested by: Peter Holm Sponsored by: The FreeBSD Foundation
This commit is contained in:
Kirk McKusick
parent
495b1baac3
commit
f0be378a66
@ -333,6 +333,8 @@ readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int flags,
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MPRINT("UFS%d superblock failed: %s (" #fmt ") %s %s (" \
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#fmt ")\n", fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, \
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#lhs, (intmax_t)lhs, #op, #rhs, (intmax_t)rhs); \
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if (error < 0) \
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return (ENOENT); \
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if (error == 0) \
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error = ENOENT; \
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}
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@ -351,6 +353,8 @@ readsuper(void *devfd, struct fs **fsp, off_t sblockloc, int flags,
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fs->fs_magic == FS_UFS1_MAGIC ? 1 : 2, #lhs1, \
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(intmax_t)lhs1, #op1, #rhs1, (intmax_t)rhs1, #lhs2, \
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(intmax_t)lhs2, #op2, #rhs2, (intmax_t)rhs2); \
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if (error < 0) \
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return (ENOENT); \
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if (error == 0) \
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error = ENOENT; \
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}
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@ -385,12 +389,16 @@ validate_sblock(struct fs *fs, int flags)
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*/
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if ((flags & UFS_FSRONLY) == UFS_FSRONLY &&
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(fs->fs_magic == FS_UFS1_MAGIC || fs->fs_magic == FS_UFS2_MAGIC)) {
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error = -1; /* fail on first error */
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if (fs->fs_magic == FS_UFS2_MAGIC) {
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FCHK(fs->fs_sblockloc, !=, SBLOCK_UFS2, %#jx);
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} else if (fs->fs_magic == FS_UFS1_MAGIC) {
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FCHK(fs->fs_sblockloc, <, 0, %jd);
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FCHK(fs->fs_sblockloc, >, SBLOCK_UFS1, %jd);
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}
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FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
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FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
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FCHK(fs->fs_sbsize % fs->fs_fsize, !=, 0, %jd);
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FCHK(fs->fs_frag, <, 1, %jd);
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FCHK(fs->fs_frag, >, MAXFRAG, %jd);
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FCHK(fs->fs_bsize, <, MINBSIZE, %jd);
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@ -438,12 +446,12 @@ validate_sblock(struct fs *fs, int flags)
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WCHK(fs->fs_old_rotdelay, !=, 0, %jd);
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WCHK(fs->fs_old_rps, !=, 60, %jd);
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WCHK(fs->fs_old_nspf, !=, fs->fs_fsize / sectorsize, %jd);
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WCHK(fs->fs_old_cpg, !=, 1, %jd);
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FCHK(fs->fs_old_cpg, !=, 1, %jd);
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WCHK(fs->fs_old_interleave, !=, 1, %jd);
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WCHK(fs->fs_old_trackskew, !=, 0, %jd);
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WCHK(fs->fs_old_cpc, !=, 0, %jd);
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WCHK(fs->fs_old_postblformat, !=, 1, %jd);
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WCHK(fs->fs_old_nrpos, !=, 1, %jd);
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FCHK(fs->fs_old_nrpos, !=, 1, %jd);
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WCHK(fs->fs_old_spc, !=, fs->fs_fpg * fs->fs_old_nspf, %jd);
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WCHK(fs->fs_old_nsect, !=, fs->fs_old_spc, %jd);
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WCHK(fs->fs_old_npsect, !=, fs->fs_old_spc, %jd);
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@ -464,10 +472,18 @@ validate_sblock(struct fs *fs, int flags)
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FCHK(powerof2(fs->fs_fsize), ==, 0, %jd);
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FCHK(fs->fs_fpg, <, 3 * fs->fs_frag, %jd);
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FCHK(fs->fs_ncg, <, 1, %jd);
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FCHK(fs->fs_ipg, <, 1, %jd);
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FCHK(fs->fs_ipg, <, fs->fs_inopb, %jd);
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FCHK(fs->fs_ipg % fs->fs_inopb, !=, 0, %jd);
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FCHK(fs->fs_ipg * fs->fs_ncg, >, (((int64_t)(1)) << 32) - INOPB(fs),
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%jd);
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FCHK(fs->fs_cstotal.cs_nifree, <, 0, %jd);
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FCHK(fs->fs_cstotal.cs_nifree, >, fs->fs_ipg * fs->fs_ncg, %jd);
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FCHK(fs->fs_cstotal.cs_ndir, <, 0, %jd);
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FCHK(fs->fs_cstotal.cs_ndir, >,
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(fs->fs_ipg * fs->fs_ncg) - fs->fs_cstotal.cs_nifree, %jd);
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FCHK(fs->fs_sbsize, >, SBLOCKSIZE, %jd);
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FCHK(fs->fs_sbsize, <, (signed)sizeof(struct fs), %jd);
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FCHK(fs->fs_sbsize % fs->fs_fsize, !=, 0, %jd);
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FCHK(fs->fs_maxbsize, <, fs->fs_bsize, %jd);
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FCHK(powerof2(fs->fs_maxbsize), ==, 0, %jd);
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FCHK(fs->fs_maxbsize, >, FS_MAXCONTIG * fs->fs_bsize, %jd);
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@ -482,6 +498,13 @@ validate_sblock(struct fs *fs, int flags)
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FCHK(fs->fs_old_cgoffset, <, 0, %jd);
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FCHK2(fs->fs_old_cgoffset, >, 0, ~fs->fs_old_cgmask, <, 0, %jd);
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FCHK(fs->fs_old_cgoffset * (~fs->fs_old_cgmask), >, fs->fs_fpg, %jd);
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/*
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* If anything has failed up to this point, it is usafe to proceed
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* as checks below may divide by zero or make other fatal calculations.
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* So if we have any errors at this point, give up.
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*/
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if (error)
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return (error);
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FCHK(fs->fs_sblkno, !=, roundup(
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howmany(fs->fs_sblockloc + SBLOCKSIZE, fs->fs_fsize),
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fs->fs_frag), %jd);
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@ -490,6 +513,8 @@ validate_sblock(struct fs *fs, int flags)
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FCHK(fs->fs_iblkno, !=, fs->fs_cblkno + fs->fs_frag, %jd);
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FCHK(fs->fs_dblkno, !=, fs->fs_iblkno + fs->fs_ipg / INOPF(fs), %jd);
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FCHK(fs->fs_cgsize, >, fs->fs_bsize, %jd);
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FCHK(fs->fs_cgsize, <, fs->fs_fsize, %jd);
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FCHK(fs->fs_cgsize % fs->fs_fsize, !=, 0, %jd);
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/*
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* This test is valid, however older versions of growfs failed
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* to correctly update fs_dsize so will fail this test. Thus we
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@ -521,8 +546,8 @@ validate_sblock(struct fs *fs, int flags)
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* and ends in the data area of the same cylinder group.
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*/
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FCHK(fs->fs_size, <, 8 * fs->fs_frag, %jd);
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WCHK(fs->fs_size, <=, (fs->fs_ncg - 1) * fs->fs_fpg, %jd);
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WCHK(fs->fs_size, >, fs->fs_ncg * fs->fs_fpg, %jd);
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FCHK(fs->fs_size, <=, (fs->fs_ncg - 1) * fs->fs_fpg, %jd);
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FCHK(fs->fs_size, >, fs->fs_ncg * fs->fs_fpg, %jd);
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/*
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* If we are not requested to read in the csum data stop here
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* as the correctness of the remaining values is only important
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@ -558,8 +583,8 @@ validate_sblock(struct fs *fs, int flags)
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*/
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WCHK(fs->fs_maxcontig, <, 0, %jd);
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WCHK(fs->fs_maxcontig, >, MAX(256, maxphys / fs->fs_bsize), %jd);
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WCHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
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WCHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
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FCHK2(fs->fs_maxcontig, ==, 0, fs->fs_contigsumsize, !=, 0, %jd);
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FCHK2(fs->fs_maxcontig, >, 1, fs->fs_contigsumsize, !=,
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MIN(fs->fs_maxcontig, FS_MAXCONTIG), %jd);
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return (error);
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}
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@ -620,8 +645,8 @@ ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
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if (ffs_sbget(devfd, &protofs, UFS_STDSB, flags, filltype,
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readfunc) == 0) {
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if (msg)
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printf("Attempted extraction of recovery data from "
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"standard superblock: ");
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printf("Attempt extraction of recovery data from "
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"standard superblock.\n");
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} else {
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/*
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* Final desperation is to see if alternate superblock
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@ -630,7 +655,7 @@ ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
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if (msg)
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printf("Attempted extraction of recovery data from "
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"standard superblock: failed\nAttempt to find "
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"boot zone recovery data: ");
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"boot zone recovery data.\n");
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/*
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* Look to see if recovery information has been saved.
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* If so we can generate a prototype superblock based
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@ -675,13 +700,19 @@ ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
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/*
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* Scan looking for alternative superblocks.
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*/
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flags = nocsum;
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if (!msg)
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flags |= UFS_NOMSG;
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for (cg = 0; cg < protofs->fs_ncg; cg++) {
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sblk = dbtob(fsbtodb(protofs, cgsblock(protofs, cg)));
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if (ffs_sbget(devfd, fsp, sblk, UFS_NOMSG | nocsum, filltype,
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sblk = fsbtodb(protofs, cgsblock(protofs, cg));
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if (msg)
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printf("Try cg %ld at sblock loc %jd\n", cg,
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(intmax_t)sblk);
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if (ffs_sbget(devfd, fsp, dbtob(sblk), flags, filltype,
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readfunc) == 0) {
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if (msg)
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printf("succeeded with alternate superblock "
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"at %jd\n", (intmax_t)btodb(sblk));
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printf("Succeeded with alternate superblock "
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"at %jd\n", (intmax_t)sblk);
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UFS_FREE(protofs, filltype);
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return (0);
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}
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@ -694,13 +725,18 @@ ffs_sbsearch(void *devfd, struct fs **fsp, int reqflags,
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trynowarn:
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flags = UFS_NOWARNFAIL | UFS_NOMSG | nocsum;
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if (msg) {
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printf("failed\n");
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printf("Finding an alternate superblock failed.\nCheck for "
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"only non-critical errors in standard superblock\n");
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flags &= ~UFS_NOMSG;
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}
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if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) != 0)
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if (ffs_sbget(devfd, fsp, UFS_STDSB, flags, filltype, readfunc) != 0) {
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if (msg)
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printf("Failed, superblock has critical errors\n");
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return (ENOENT);
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}
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if (msg)
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printf("Using standard superblock with non-critical errors.\n");
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printf("Success, using standard superblock with "
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"non-critical errors.\n");
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return (0);
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}
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