From patchwork Sat Jan 21 08:09:09 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Darrick J. Wong" X-Patchwork-Id: 9530065 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id 080D2600CA for ; Sat, 21 Jan 2017 08:09:19 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id E7DAB2842E for ; Sat, 21 Jan 2017 08:09:18 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id DB4FC28695; Sat, 21 Jan 2017 08:09:18 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00, RCVD_IN_DNSWL_HI, UNPARSEABLE_RELAY autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9780F2842E for ; Sat, 21 Jan 2017 08:09:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751169AbdAUIJQ (ORCPT ); Sat, 21 Jan 2017 03:09:16 -0500 Received: from userp1040.oracle.com ([156.151.31.81]:26014 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751137AbdAUIJQ (ORCPT ); Sat, 21 Jan 2017 03:09:16 -0500 Received: from aserv0022.oracle.com (aserv0022.oracle.com [141.146.126.234]) by userp1040.oracle.com (Sentrion-MTA-4.3.2/Sentrion-MTA-4.3.2) with ESMTP id v0L89Ceo024520 (version=TLSv1.2 cipher=ECDHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 21 Jan 2017 08:09:13 GMT Received: from userv0122.oracle.com (userv0122.oracle.com [156.151.31.75]) by aserv0022.oracle.com (8.14.4/8.14.4) with ESMTP id v0L89CCk028081 (version=TLSv1/SSLv3 cipher=DHE-RSA-AES256-GCM-SHA384 bits=256 verify=OK); Sat, 21 Jan 2017 08:09:12 GMT Received: from abhmp0016.oracle.com (abhmp0016.oracle.com [141.146.116.22]) by userv0122.oracle.com (8.14.4/8.14.4) with ESMTP id v0L89B8Y008614; Sat, 21 Jan 2017 08:09:11 GMT Received: from localhost (/24.21.211.40) by default (Oracle Beehive Gateway v4.0) with ESMTP ; Sat, 21 Jan 2017 00:09:11 -0800 Subject: [PATCH 09/17] xfs_db: introduce fuzz command From: "Darrick J. Wong" To: sandeen@redhat.com, darrick.wong@oracle.com Cc: linux-xfs@vger.kernel.org, linux-fsdevel@vger.kernel.org Date: Sat, 21 Jan 2017 00:09:09 -0800 Message-ID: <148498614970.16675.13773024118867518517.stgit@birch.djwong.org> In-Reply-To: <148498608472.16675.14848042961636871812.stgit@birch.djwong.org> References: <148498608472.16675.14848042961636871812.stgit@birch.djwong.org> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 X-Source-IP: aserv0022.oracle.com [141.146.126.234] Sender: linux-xfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-xfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Introduce a new 'fuzz' command to write creative values into disk structure fields. Signed-off-by: Darrick J. Wong --- db/Makefile | 3 db/bit.c | 17 +- db/bit.h | 5 - db/command.c | 2 db/fuzz.c | 461 +++++++++++++++++++++++++++++++++++++++++++++++++++++ db/fuzz.h | 21 ++ db/io.c | 9 + db/io.h | 1 db/type.c | 44 ++++- db/type.h | 1 man/man8/xfs_db.8 | 55 ++++++ 11 files changed, 598 insertions(+), 21 deletions(-) create mode 100644 db/fuzz.c create mode 100644 db/fuzz.h -- To unsubscribe from this list: send the line "unsubscribe linux-xfs" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html diff --git a/db/Makefile b/db/Makefile index cdc0b99..feeacf6 100644 --- a/db/Makefile +++ b/db/Makefile @@ -12,7 +12,8 @@ HFILES = addr.h agf.h agfl.h agi.h attr.h attrshort.h bit.h block.h bmap.h \ dir2.h dir2sf.h dquot.h echo.h faddr.h field.h \ flist.h fprint.h frag.h freesp.h hash.h help.h init.h inode.h input.h \ io.h logformat.h malloc.h metadump.h output.h print.h quit.h sb.h \ - sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h + sig.h strvec.h text.h type.h write.h attrset.h symlink.h fsmap.h \ + fuzz.h CFILES = $(HFILES:.h=.c) LSRCFILES = xfs_admin.sh xfs_ncheck.sh xfs_metadump.sh diff --git a/db/bit.c b/db/bit.c index 24872bf..3fcb085 100644 --- a/db/bit.c +++ b/db/bit.c @@ -19,13 +19,8 @@ #include "libxfs.h" #include "bit.h" -#undef setbit /* defined in param.h on Linux */ - -static int getbit(char *ptr, int bit); -static void setbit(char *ptr, int bit, int val); - -static int -getbit( +int +getbit_l( char *ptr, int bit) { @@ -39,8 +34,8 @@ getbit( return (*ptr & mask) >> shift; } -static void -setbit( +void +setbit_l( char *ptr, int bit, int val) @@ -106,7 +101,7 @@ getbitval( for (i = 0, rval = 0LL; i < nbits; i++) { - if (getbit(p, bit + i)) { + if (getbit_l(p, bit + i)) { /* If the last bit is on and we care about sign * bits and we don't have a full 64 bit * container, turn all bits on between the @@ -162,7 +157,7 @@ setbitval( if (bitoff % NBBY || nbits % NBBY) { for (bit = 0; bit < nbits; bit++) - setbit(out, bit + bitoff, getbit(in, bit)); + setbit_l(out, bit + bitoff, getbit_l(in, bit)); } else memcpy(out + byteize(bitoff), in, byteize(nbits)); } diff --git a/db/bit.h b/db/bit.h index 80ba24c..4506679 100644 --- a/db/bit.h +++ b/db/bit.h @@ -21,9 +21,12 @@ #define bitszof(x,y) bitize(szof(x,y)) #define byteize(s) ((s) / NBBY) #define bitoffs(s) ((s) % NBBY) +#define byteize_up(s) (((s) + NBBY - 1) / NBBY) #define BVUNSIGNED 0 #define BVSIGNED 1 extern __int64_t getbitval(void *obj, int bitoff, int nbits, int flags); -extern void setbitval(void *obuf, int bitoff, int nbits, void *ibuf); +extern void setbitval(void *obuf, int bitoff, int nbits, void *ibuf); +extern int getbit_l(char *ptr, int bit); +extern void setbit_l(char *ptr, int bit, int val); diff --git a/db/command.c b/db/command.c index 3d7cfd7..0eb4944 100644 --- a/db/command.c +++ b/db/command.c @@ -51,6 +51,7 @@ #include "dquot.h" #include "fsmap.h" #include "crc.h" +#include "fuzz.h" cmdinfo_t *cmdtab; int ncmds; @@ -146,4 +147,5 @@ init_commands(void) type_init(); write_init(); dquot_init(); + fuzz_init(); } diff --git a/db/fuzz.c b/db/fuzz.c new file mode 100644 index 0000000..061ecd1 --- /dev/null +++ b/db/fuzz.c @@ -0,0 +1,461 @@ +/* + * Copyright (c) 2000-2002,2005 Silicon Graphics, Inc. + * All Rights Reserved. + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License as + * published by the Free Software Foundation. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA + */ + +#include "libxfs.h" +#include +#include +#include "bit.h" +#include "block.h" +#include "command.h" +#include "type.h" +#include "faddr.h" +#include "fprint.h" +#include "field.h" +#include "flist.h" +#include "io.h" +#include "init.h" +#include "output.h" +#include "print.h" +#include "write.h" +#include "malloc.h" + +static int fuzz_f(int argc, char **argv); +static void fuzz_help(void); + +static const cmdinfo_t fuzz_cmd = + { "fuzz", NULL, fuzz_f, 0, -1, 0, N_("[-c] [-d] field fuzzcmd..."), + N_("fuzz values on disk"), fuzz_help }; + +void +fuzz_init(void) +{ + if (!expert_mode) + return; + + add_command(&fuzz_cmd); + srand48(clock()); +} + +static void +fuzz_help(void) +{ + dbprintf(_( +"\n" +" The 'fuzz' command fuzzes fields in any on-disk data structure. For\n" +" block fuzzing, see the 'blocktrash' or 'write' commands." +"\n" +" Examples:\n" +" Struct mode: 'fuzz core.uid zeroes' - set an inode uid field to 0.\n" +" 'fuzz crc ones' - set a crc filed to all ones.\n" +" 'fuzz bno[11] firstbit' - set the high bit of a block array.\n" +" 'fuzz keys[5].startblock add' - increase a btree key value.\n" +" 'fuzz uuid random' - randomize the superblock uuid.\n" +"\n" +" In data mode type 'fuzz' by itself for a list of specific commands.\n\n" +" Specifying the -c option will allow writes of invalid (corrupt) data with\n" +" an invalid CRC. Specifying the -d option will allow writes of invalid data,\n" +" but still recalculate the CRC so we are forced to check and detect the\n" +" invalid data appropriately.\n\n" +)); + +} + +static int +fuzz_f( + int argc, + char **argv) +{ + pfunc_t pf; + extern char *progname; + int c; + bool corrupt = false; /* Allow write of bad data w/ invalid CRC */ + bool invalid_data = false; /* Allow write of bad data w/ valid CRC */ + struct xfs_buf_ops local_ops; + const struct xfs_buf_ops *stashed_ops = NULL; + + if (x.isreadonly & LIBXFS_ISREADONLY) { + dbprintf(_("%s started in read only mode, fuzzing disabled\n"), + progname); + return 0; + } + + if (cur_typ == NULL) { + dbprintf(_("no current type\n")); + return 0; + } + + pf = cur_typ->pfunc; + if (pf == NULL) { + dbprintf(_("no handler function for type %s, fuzz unsupported.\n"), + cur_typ->name); + return 0; + } + + while ((c = getopt(argc, argv, "cd")) != EOF) { + switch (c) { + case 'c': + corrupt = true; + break; + case 'd': + invalid_data = true; + break; + default: + dbprintf(_("bad option for fuzz command\n")); + return 0; + } + } + + if (corrupt && invalid_data) { + dbprintf(_("Cannot specify both -c and -d options\n")); + return 0; + } + + if (invalid_data && iocur_top->typ->crc_off == TYP_F_NO_CRC_OFF && + !iocur_top->ino_buf) { + dbprintf(_("Cannot recalculate CRCs on this type of object\n")); + return 0; + } + + argc -= optind; + argv += optind; + + /* + * If the buffer has no verifier or we are using standard verifier + * paths, then just fuzz it and return + */ + if (!iocur_top->bp->b_ops || + !(corrupt || invalid_data)) { + (*pf)(DB_FUZZ, cur_typ->fields, argc, argv); + return 0; + } + + + /* Temporarily remove write verifier to write bad data */ + stashed_ops = iocur_top->bp->b_ops; + local_ops.verify_read = stashed_ops->verify_read; + iocur_top->bp->b_ops = &local_ops; + + if (corrupt) { + local_ops.verify_write = xfs_dummy_verify; + dbprintf(_("Allowing fuzz of corrupted data and bad CRC\n")); + } else if (iocur_top->ino_buf) { + local_ops.verify_write = xfs_verify_recalc_inode_crc; + dbprintf(_("Allowing fuzz of corrupted inode with good CRC\n")); + } else { /* invalid data */ + local_ops.verify_write = xfs_verify_recalc_crc; + dbprintf(_("Allowing fuzz of corrupted data with good CRC\n")); + } + + (*pf)(DB_FUZZ, cur_typ->fields, argc, argv); + + iocur_top->bp->b_ops = stashed_ops; + + return 0; +} + +/* Write zeroes to the field */ +static bool +fuzz_zeroes( + void *buf, + int bitoff, + int nbits) +{ + char *out = buf; + int bit; + + if (bitoff % NBBY || nbits % NBBY) { + for (bit = 0; bit < nbits; bit++) + setbit_l(out, bit + bitoff, 0); + } else + memset(out + byteize(bitoff), 0, byteize(nbits)); + return true; +} + +/* Write ones to the field */ +static bool +fuzz_ones( + void *buf, + int bitoff, + int nbits) +{ + char *out = buf; + int bit; + + if (bitoff % NBBY || nbits % NBBY) { + for (bit = 0; bit < nbits; bit++) + setbit_l(out, bit + bitoff, 1); + } else + memset(out + byteize(bitoff), 0xFF, byteize(nbits)); + return true; +} + +/* Flip the high bit in the (presumably big-endian) field */ +static bool +fuzz_firstbit( + void *buf, + int bitoff, + int nbits) +{ + setbit_l((char *)buf, bitoff, !getbit_l((char *)buf, bitoff)); + return true; +} + +/* Flip the low bit in the (presumably big-endian) field */ +static bool +fuzz_lastbit( + void *buf, + int bitoff, + int nbits) +{ + setbit_l((char *)buf, bitoff + nbits - 1, + !getbit_l((char *)buf, bitoff)); + return true; +} + +/* Flip the middle bit in the (presumably big-endian) field */ +static bool +fuzz_middlebit( + void *buf, + int bitoff, + int nbits) +{ + setbit_l((char *)buf, bitoff + nbits / 2, + !getbit_l((char *)buf, bitoff)); + return true; +} + +/* Format and shift a number into a buffer for setbitval. */ +static char * +format_number( + uint64_t val, + __be64 *out, + int bit_length) +{ + int offset; + char *rbuf = (char *)out; + + /* + * If the length of the field is not a multiple of a byte, push + * the bits up in the field, so the most signicant field bit is + * the most significant bit in the byte: + * + * before: + * val |----|----|----|----|----|--MM|mmmm|llll| + * after + * val |----|----|----|----|----|MMmm|mmll|ll00| + */ + offset = bit_length % NBBY; + if (offset) + val <<= (NBBY - offset); + + /* + * convert to big endian and copy into the array + * rbuf |----|----|----|----|----|MMmm|mmll|ll00| + */ + *out = cpu_to_be64(val); + + /* + * Align the array to point to the field in the array. + * rbuf = |MMmm|mmll|ll00| + */ + offset = sizeof(__be64) - 1 - ((bit_length - 1) / sizeof(__be64)); + return rbuf + offset; +} + +/* Increase the value by some small prime number. */ +static bool +fuzz_add( + void *buf, + int bitoff, + int nbits) +{ + uint64_t val; + __be64 out; + char *b; + + if (nbits > 64) + return false; + + val = getbitval(buf, bitoff, nbits, BVUNSIGNED); + val += (nbits > 8 ? 2017 : 137); + b = format_number(val, &out, nbits); + setbitval(buf, bitoff, nbits, b); + + return true; +} + +/* Decrease the value by some small prime number. */ +static bool +fuzz_sub( + void *buf, + int bitoff, + int nbits) +{ + uint64_t val; + __be64 out; + char *b; + + if (nbits > 64) + return false; + + val = getbitval(buf, bitoff, nbits, BVUNSIGNED); + val -= (nbits > 8 ? 2017 : 137); + b = format_number(val, &out, nbits); + setbitval(buf, bitoff, nbits, b); + + return true; +} + +/* Randomize the field. */ +static bool +fuzz_random( + void *buf, + int bitoff, + int nbits) +{ + int i, bytes; + char *b, *rbuf; + + bytes = byteize_up(nbits); + rbuf = b = malloc(bytes); + if (!b) { + perror("fuzz_random"); + return false; + } + + for (i = 0; i < bytes; i++) + *b++ = (char)lrand48(); + + setbitval(buf, bitoff, nbits, rbuf); + free(rbuf); + + return true; +} + +struct fuzzcmd { + const char *verb; + bool (*fn)(void *buf, int bitoff, int nbits); +}; + +/* Keep these verbs in sync with enum fuzzcmds. */ +static struct fuzzcmd fuzzverbs[] = { + {"zeroes", fuzz_zeroes}, + {"ones", fuzz_ones}, + {"firstbit", fuzz_firstbit}, + {"middlebit", fuzz_middlebit}, + {"lastbit", fuzz_lastbit}, + {"add", fuzz_add}, + {"sub", fuzz_sub}, + {"random", fuzz_random}, + {NULL, NULL}, +}; + +/* ARGSUSED */ +void +fuzz_struct( + const field_t *fields, + int argc, + char **argv) +{ + const ftattr_t *fa; + flist_t *fl; + flist_t *sfl; + int bit_length; + struct fuzzcmd *fc; + bool success; + int parentoffset; + + if (argc != 2) { + dbprintf(_("Usage: fuzz fieldname verb\n")); + dbprintf("Verbs: %s", fuzzverbs->verb); + for (fc = fuzzverbs + 1; fc->verb != NULL; fc++) + dbprintf(", %s", fc->verb); + dbprintf(".\n"); + return; + } + + fl = flist_scan(argv[0]); + if (!fl) { + dbprintf(_("unable to parse '%s'.\n"), argv[0]); + return; + } + + /* Find our fuzz verb */ + for (fc = fuzzverbs; fc->verb != NULL; fc++) + if (!strcmp(fc->verb, argv[1])) + break; + if (fc->fn == NULL) { + dbprintf(_("Unknown fuzz command '%s'.\n"), argv[1]); + return; + } + + /* if we're a root field type, go down 1 layer to get field list */ + if (fields->name[0] == '\0') { + fa = &ftattrtab[fields->ftyp]; + ASSERT(fa->ftyp == fields->ftyp); + fields = fa->subfld; + } + + /* run down the field list and set offsets into the data */ + if (!flist_parse(fields, fl, iocur_top->data, 0)) { + flist_free(fl); + dbprintf(_("parsing error\n")); + return; + } + + sfl = fl; + parentoffset = 0; + while (sfl->child) { + parentoffset = sfl->offset; + sfl = sfl->child; + } + + /* + * For structures, fsize * fcount tells us the size of the region we are + * modifying, which is usually a single structure member and is pointed + * to by the last child in the list. + * + * However, if the base structure is an array and we have a direct index + * into the array (e.g. write bno[5]) then we are returned a single + * flist object with the offset pointing directly at the location we + * need to modify. The length of the object we are modifying is then + * determined by the size of the individual array entry (fsize) and the + * indexes defined in the object, not the overall size of the array + * (which is what fcount returns). + */ + bit_length = fsize(sfl->fld, iocur_top->data, parentoffset, 0); + if (sfl->fld->flags & FLD_ARRAY) + bit_length *= sfl->high - sfl->low + 1; + else + bit_length *= fcount(sfl->fld, iocur_top->data, parentoffset); + + /* Fuzz the value */ + success = fc->fn(iocur_top->data, sfl->offset, bit_length); + if (!success) { + dbprintf(_("unable to fuzz field '%s'\n"), argv[0]); + flist_free(fl); + return; + } + + /* Write the fuzzed value back */ + write_cur(); + + flist_print(fl); + print_flist(fl); + flist_free(fl); +} diff --git a/db/fuzz.h b/db/fuzz.h new file mode 100644 index 0000000..c203eb5 --- /dev/null +++ b/db/fuzz.h @@ -0,0 +1,21 @@ +/* + * Copyright (C) 2017 Oracle. All Rights Reserved. + * + * Author: Darrick J. Wong + * + * This program is free software; you can redistribute it and/or + * modify it under the terms of the GNU General Public License + * as published by the Free Software Foundation; either version 2 + * of the License, or (at your option) any later version. + * + * This program is distributed in the hope that it would be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write the Free Software Foundation, + * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. + */ +extern void fuzz_init(void); +extern void fuzz_struct(const field_t *fields, int argc, char **argv); diff --git a/db/io.c b/db/io.c index f398195..1f316d8 100644 --- a/db/io.c +++ b/db/io.c @@ -465,6 +465,15 @@ xfs_dummy_verify( } void +xfs_verify_recalc_inode_crc( + struct xfs_buf *bp) +{ + ASSERT(iocur_top->ino_buf); + libxfs_dinode_calc_crc(mp, iocur_top->data); + iocur_top->ino_crc_ok = 1; +} + +void xfs_verify_recalc_crc( struct xfs_buf *bp) { diff --git a/db/io.h b/db/io.h index c69e9ce..12d96c2 100644 --- a/db/io.h +++ b/db/io.h @@ -64,6 +64,7 @@ extern void set_cur(const struct typ *t, __int64_t d, int c, int ring_add, extern void ring_add(void); extern void set_iocur_type(const struct typ *t); extern void xfs_dummy_verify(struct xfs_buf *bp); +extern void xfs_verify_recalc_inode_crc(struct xfs_buf *bp); extern void xfs_verify_recalc_crc(struct xfs_buf *bp); /* diff --git a/db/type.c b/db/type.c index 10fa54e..adab10a 100644 --- a/db/type.c +++ b/db/type.c @@ -39,6 +39,7 @@ #include "dir2.h" #include "text.h" #include "symlink.h" +#include "fuzz.h" static const typ_t *findtyp(char *name); static int type_f(int argc, char **argv); @@ -254,10 +255,17 @@ handle_struct( int argc, char **argv) { - if (action == DB_WRITE) + switch (action) { + case DB_FUZZ: + fuzz_struct(fields, argc, argv); + break; + case DB_WRITE: write_struct(fields, argc, argv); - else + break; + case DB_READ: print_struct(fields, argc, argv); + break; + } } void @@ -267,10 +275,17 @@ handle_string( int argc, char **argv) { - if (action == DB_WRITE) + switch (action) { + case DB_WRITE: write_string(fields, argc, argv); - else + break; + case DB_READ: print_string(fields, argc, argv); + break; + case DB_FUZZ: + dbprintf(_("string fuzzing not supported.\n")); + break; + } } void @@ -280,10 +295,17 @@ handle_block( int argc, char **argv) { - if (action == DB_WRITE) + switch (action) { + case DB_WRITE: write_block(fields, argc, argv); - else + break; + case DB_READ: print_block(fields, argc, argv); + break; + case DB_FUZZ: + dbprintf(_("use 'blocktrash' or 'write' to fuzz a block.\n")); + break; + } } void @@ -293,6 +315,14 @@ handle_text( int argc, char **argv) { - if (action != DB_WRITE) + switch (action) { + case DB_FUZZ: + /* fall through */ + case DB_WRITE: + dbprintf(_("text writing/fuzzing not supported.\n")); + break; + case DB_READ: print_text(fields, argc, argv); + break; + } } diff --git a/db/type.h b/db/type.h index 87ff107..a50d705 100644 --- a/db/type.h +++ b/db/type.h @@ -30,6 +30,7 @@ typedef enum typnm TYP_TEXT, TYP_FINOBT, TYP_NONE } typnm_t; +#define DB_FUZZ 2 #define DB_WRITE 1 #define DB_READ 0 diff --git a/man/man8/xfs_db.8 b/man/man8/xfs_db.8 index 460d89d..55e0629 100644 --- a/man/man8/xfs_db.8 +++ b/man/man8/xfs_db.8 @@ -594,6 +594,55 @@ in units of 512-byte blocks, no matter what the filesystem's block size is. .BI "The optional " start " and " end " arguments can be used to constrain the output to a particular range of disk blocks. .TP +.BI "fuzz [\-c] [\-d] " "field action" +Write garbage into a specific structure field on disk. +Expert mode must be enabled to use this command. +The operation happens immediately; there is no buffering. +.IP +The fuzz command can take the following +.IR action "s" +against a field: +.RS 1.0i +.TP 0.4i +.B zeroes +Clears all bits in the field. +.TP 0.4i +.B ones +Sets all bits in the field. +.TP 0.4i +.B firstbit +Flips the first bit in the field. +For a scalar value, this is the highest bit. +.TP 0.4i +.B middlebit +Flips the middle bit in the field. +.TP 0.4i +.B lastbit +Flips the last bit in the field. +For a scalar value, this is the lowest bit. +.TP 0.4i +.B add +Adds a small value to a scalar field. +.TP 0.4i +.B sub +Subtracts a small value from a scalar field. +.TP 0.4i +.B random +Randomizes the contents of the field. +.RE +.IP +The following switches affect the write behavior: +.RS 1.0i +.TP 0.4i +.B \-c +Skip write verifiers and CRC recalculation; allows invalid data to be written +to disk. +.TP 0.4i +.B \-d +Skip write verifiers but perform CRC recalculation; allows invalid data to be +written to disk to test detection of invalid data. +.RE +.TP .BI hash " string Prints the hash value of .I string @@ -755,7 +804,7 @@ and bits respectively, and their string equivalent reported (but no modifications are made). .TP -.BI "write [\-c] [" "field value" "] ..." +.BI "write [\-c] [\-d] [" "field value" "] ..." Write a value to disk. Specific fields can be set in structures (struct mode), or a block can be set to data values (data mode), @@ -778,6 +827,10 @@ with no arguments gives more information on the allowed commands. .B \-c Skip write verifiers and CRC recalculation; allows invalid data to be written to disk. +.TP 0.4i +.B \-d +Skip write verifiers but perform CRC recalculation; allows invalid data to be +written to disk to test detection of invalid data. .RE .SH TYPES This section gives the fields in each structure type and their meanings.