155 lines
5.5 KiB
Diff
155 lines
5.5 KiB
Diff
From: Thomas Habets <habets@google.com>
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Subject: [PATCH] Check for size overflow in tar header fields.
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This prevents surprising outputs being created, e.g. this cpio tar
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output with more than one file:
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tar cf suffix.tar AUTHORS
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dd if=/dev/zero seek=16G bs=1 count=0 of=suffix.tar
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echo suffix.tar | cpio -H tar -o | tar tvf -
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-rw-r--r-- 1000/1000 0 2019-08-30 16:40 suffix.tar
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-rw-r--r-- thomas/thomas 161 2019-08-30 16:40 AUTHORS
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---
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src/copyout.c | 3 +--
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src/extern.h | 2 +-
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src/tar.c | 45 ++++++++++++++++++++++++++++++++-------------
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3 files changed, 34 insertions(+), 16 deletions(-)
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diff --git a/src/copyout.c b/src/copyout.c
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index dcae449..56416ba 100644
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--- a/src/copyout.c
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+++ b/src/copyout.c
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@@ -552,8 +552,7 @@ write_out_header (struct cpio_file_stat *file_hdr, int out_des)
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error (0, 0, _("%s: file name too long"), file_hdr->c_name);
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return 1;
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}
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- write_out_tar_header (file_hdr, out_des); /* FIXME: No error checking */
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- return 0;
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+ return write_out_tar_header (file_hdr, out_des);
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case arf_binary:
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return write_out_binary_header (makedev (file_hdr->c_rdev_maj,
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diff --git a/src/extern.h b/src/extern.h
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index e27d662..47b477a 100644
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--- a/src/extern.h
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+++ b/src/extern.h
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@@ -145,7 +145,7 @@ int make_path (char *argpath, uid_t owner, gid_t group,
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const char *verbose_fmt_string);
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/* tar.c */
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-void write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des);
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+int write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des);
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int null_block (long *block, int size);
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void read_in_tar_header (struct cpio_file_stat *file_hdr, int in_des);
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int otoa (char *s, unsigned long *n);
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diff --git a/src/tar.c b/src/tar.c
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index e2b5f45..53dc99a 100644
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--- a/src/tar.c
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+++ b/src/tar.c
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@@ -93,8 +93,9 @@ stash_tar_filename (char *prefix, char *filename)
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sprintf (where, "%*lo ", digits - 2, value);
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except that sprintf fills in the trailing NUL and we don't. */
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-static void
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-to_oct (register long value, register int digits, register char *where)
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+static int
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+to_oct_or_error (register long value, register int digits, register char *where,
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+ const char *filename, const char *fieldname)
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{
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--digits; /* Leave the trailing NUL slot alone. */
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@@ -105,10 +106,17 @@ to_oct (register long value, register int digits, register char *where)
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value >>= 3;
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}
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while (digits > 0 && value != 0);
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+ if (value > 0)
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+ {
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+ error (0, 0, _("%s: field width not sufficient for storing %s"),
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+ filename, fieldname);
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+ return 1;
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+ }
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/* Add leading zeroes, if necessary. */
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while (digits > 0)
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where[--digits] = '0';
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+ return 0;
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}
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@@ -139,7 +147,7 @@ tar_checksum (struct tar_header *tar_hdr)
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/* Write out header FILE_HDR, including the file name, to file
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descriptor OUT_DES. */
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-void
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+int
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write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des)
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{
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int name_len;
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@@ -168,11 +176,16 @@ write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des)
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/* Ustar standard (POSIX.1-1988) requires the mode to contain only 3 octal
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digits */
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- to_oct (file_hdr->c_mode & MODE_ALL, 8, tar_hdr->mode);
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- to_oct (file_hdr->c_uid, 8, tar_hdr->uid);
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- to_oct (file_hdr->c_gid, 8, tar_hdr->gid);
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- to_oct (file_hdr->c_filesize, 12, tar_hdr->size);
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- to_oct (file_hdr->c_mtime, 12, tar_hdr->mtime);
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+ if (to_oct_or_error (file_hdr->c_mode & MODE_ALL, 8, tar_hdr->mode, file_hdr->c_name, _("mode")))
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+ return 1;
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+ if (to_oct_or_error (file_hdr->c_uid, 8, tar_hdr->uid, file_hdr->c_name, _("uid")))
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+ return 1;
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+ if (to_oct_or_error (file_hdr->c_gid, 8, tar_hdr->gid, file_hdr->c_name, _("gid")))
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+ return 1;
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+ if (to_oct_or_error (file_hdr->c_filesize, 12, tar_hdr->size, file_hdr->c_name, _("file size")))
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+ return 1;
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+ if (to_oct_or_error (file_hdr->c_mtime, 12, tar_hdr->mtime, file_hdr->c_name, _("modification time")))
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+ return 1;
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switch (file_hdr->c_mode & CP_IFMT)
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{
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@@ -184,7 +197,8 @@ write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des)
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strncpy (tar_hdr->linkname, file_hdr->c_tar_linkname,
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TARLINKNAMESIZE);
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tar_hdr->typeflag = LNKTYPE;
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- to_oct (0, 12, tar_hdr->size);
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+ if (to_oct_or_error (0, 12, tar_hdr->size, file_hdr->c_name, _("file size")))
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+ return 1;
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}
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else
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tar_hdr->typeflag = REGTYPE;
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@@ -210,7 +224,8 @@ write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des)
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than TARLINKNAMESIZE. */
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strncpy (tar_hdr->linkname, file_hdr->c_tar_linkname,
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TARLINKNAMESIZE);
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- to_oct (0, 12, tar_hdr->size);
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+ if (to_oct_or_error (0, 12, tar_hdr->size, file_hdr->c_name, _("file size")))
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+ return 1;
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break;
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#endif /* CP_IFLNK */
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}
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@@ -229,13 +244,17 @@ write_out_tar_header (struct cpio_file_stat *file_hdr, int out_des)
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if (name)
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strcpy (tar_hdr->gname, name);
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- to_oct (file_hdr->c_rdev_maj, 8, tar_hdr->devmajor);
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- to_oct (file_hdr->c_rdev_min, 8, tar_hdr->devminor);
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+ if (to_oct_or_error (file_hdr->c_rdev_maj, 8, tar_hdr->devmajor, file_hdr->c_name, _("rdev major")))
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+ return 1;
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+ if (to_oct_or_error (file_hdr->c_rdev_min, 8, tar_hdr->devminor, file_hdr->c_name, _("rdev minor")))
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+ return 1;
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}
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- to_oct (tar_checksum (tar_hdr), 8, tar_hdr->chksum);
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+ if (to_oct_or_error (tar_checksum (tar_hdr), 8, tar_hdr->chksum, file_hdr->c_name, _("checksum")))
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+ return 1;
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tape_buffered_write ((char *) &tar_rec, out_des, TARRECORDSIZE);
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+ return 0;
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}
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/* Return nonzero iff all the bytes in BLOCK are NUL.
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--
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2.26.0
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