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d45b67c5f2
When passed a negative count (indicating a byte count rather than a block count) e2fsck_handle_read_error() treats the data as a full block, causing unix_write_blk64() (which can handle negative counts just fine) to try to write too much. Given a faulty block device, this resulted in a SEGV when unix_write_blk64() read past the bottom of the stack copying the data to cache. (check_backup_super_block -> unix_read_blk64 -> raw_read_blk -> e2fsck_handle_read_error) Reported-by: Alex Friedman <alexfr@il.ibm.com> Signed-off-by: Jim Keniston <jkenisto@us.ibm.com> Signed-off-by: Dan Streetman <ddstreet@us.ibm.com> Reviewed-by: Mingming Cao <mcao@us.ibm.com> Signed-off-by: Theodore Ts'o <tytso@mit.edu>
129 lines
3.0 KiB
C
129 lines
3.0 KiB
C
/*
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* ehandler.c --- handle bad block errors which come up during the
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* course of an e2fsck session.
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*
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* Copyright (C) 1994 Theodore Ts'o. This file may be redistributed
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* under the terms of the GNU Public License.
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*/
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#include "config.h"
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#include <stdlib.h>
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#include <unistd.h>
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#include <string.h>
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#include <ctype.h>
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#include <termios.h>
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#include "e2fsck.h"
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#include <sys/time.h>
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#include <sys/resource.h>
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static const char *operation;
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static errcode_t e2fsck_handle_read_error(io_channel channel,
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unsigned long block,
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int count,
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void *data,
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size_t size EXT2FS_ATTR((unused)),
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int actual EXT2FS_ATTR((unused)),
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errcode_t error)
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{
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int i;
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char *p;
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ext2_filsys fs = (ext2_filsys) channel->app_data;
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e2fsck_t ctx;
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ctx = (e2fsck_t) fs->priv_data;
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if (ctx->flags & E2F_FLAG_EXITING)
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return 0;
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/*
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* If more than one block was read, try reading each block
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* separately. We could use the actual bytes read to figure
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* out where to start, but we don't bother.
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*/
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if (count > 1) {
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p = (char *) data;
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for (i=0; i < count; i++, p += channel->block_size, block++) {
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error = io_channel_read_blk64(channel, block,
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1, p);
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if (error)
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return error;
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}
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return 0;
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}
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if (operation)
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printf(_("Error reading block %lu (%s) while %s. "), block,
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error_message(error), operation);
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else
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printf(_("Error reading block %lu (%s). "), block,
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error_message(error));
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preenhalt(ctx);
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if (ask(ctx, _("Ignore error"), 1)) {
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if (ask(ctx, _("Force rewrite"), 1))
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io_channel_write_blk64(channel, block, count, data);
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return 0;
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}
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return error;
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}
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static errcode_t e2fsck_handle_write_error(io_channel channel,
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unsigned long block,
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int count,
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const void *data,
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size_t size EXT2FS_ATTR((unused)),
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int actual EXT2FS_ATTR((unused)),
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errcode_t error)
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{
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int i;
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const char *p;
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ext2_filsys fs = (ext2_filsys) channel->app_data;
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e2fsck_t ctx;
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ctx = (e2fsck_t) fs->priv_data;
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if (ctx->flags & E2F_FLAG_EXITING)
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return 0;
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/*
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* If more than one block was written, try writing each block
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* separately. We could use the actual bytes read to figure
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* out where to start, but we don't bother.
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*/
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if (count > 1) {
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p = (const char *) data;
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for (i=0; i < count; i++, p += channel->block_size, block++) {
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error = io_channel_write_blk64(channel, block,
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1, p);
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if (error)
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return error;
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}
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return 0;
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}
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if (operation)
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printf(_("Error writing block %lu (%s) while %s. "), block,
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error_message(error), operation);
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else
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printf(_("Error writing block %lu (%s). "), block,
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error_message(error));
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preenhalt(ctx);
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if (ask(ctx, _("Ignore error"), 1))
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return 0;
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return error;
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}
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const char *ehandler_operation(const char *op)
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{
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const char *ret = operation;
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operation = op;
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return ret;
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}
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void ehandler_init(io_channel channel)
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{
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channel->read_error = e2fsck_handle_read_error;
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channel->write_error = e2fsck_handle_write_error;
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}
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