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Date:      Thu, 01 Dec 2016 18:46:25 -0800
From:      Cy Schubert <Cy.Schubert@komquats.com>
To:        Cy Schubert <Cy.Schubert@komquats.com>
Cc:        Martin Matuska <mm@FreeBSD.org>, src-committers@freebsd.org, svn-src-all@freebsd.org, svn-src-head@freebsd.org
Subject:   Re: svn commit: r309300 - in head: contrib/libarchive  contrib/libarchive/libarchive contrib/libarchive/libarchive/test  contrib/libarchive/tar/test lib/libarchive/tests
Message-ID:  <201612020246.uB22kPal051798@slippy.cwsent.com>
In-Reply-To: Message from Cy Schubert <Cy.Schubert@komquats.com> of "Thu, 01 Dec 2016 18:25:18 -0800." <201612020225.uB22PIQl039020@slippy.cwsent.com>

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In message <201612020225.uB22PIQl039020@slippy.cwsent.com>, Cy Schubert 
writes:
> In message <201611292214.uATMEgQH079904@repo.freebsd.org>, Martin Matuska 
> write
> s:
> > Author: mm
> > Date: Tue Nov 29 22:14:42 2016
> > New Revision: 309300
> > URL: https://svnweb.freebsd.org/changeset/base/309300
> > 
> > Log:
> >   MFV r309299:
> >   Sync libarchive with vendor.
> >   
> >   Important vendor bugfixes (relevant to FreeBSD):
> >   #821: tar -P cannot extract hardlinks through symlinks
> >   #825: Add sanity check of tar "uid, "gid" and "mtime" fields
> >   
> >   PR:		213255
> >   Reported by:	Tijl Coosemans <tilj@FreeBSD.org>
> >   MFC after:	1 week
> > 
> > Added:
> >   head/contrib/libarchive/libarchive/test/test_compat_gtar_2.tar.uu
> >      - copied unchanged from r309299, vendor/libarchive/dist/libarchive/tes
> t/
> > test_compat_gtar_2.tar.uu
> >   head/contrib/libarchive/libarchive/test/test_compat_star_acl_posix1e.c
> >      - copied unchanged from r309299, vendor/libarchive/dist/libarchive/tes
> t/
> > test_compat_star_acl_posix1e.c
> >   head/contrib/libarchive/libarchive/test/test_compat_star_acl_posix1e.tar.
> uu
> >      - copied unchanged from r309299, vendor/libarchive/dist/libarchive/tes
> t/
> > test_compat_star_acl_posix1e.tar.uu
> >   head/contrib/libarchive/libarchive/test/test_read_format_raw.bufr.uu
> >      - copied unchanged from r309299, vendor/libarchive/dist/libarchive/tes
> t/
> > test_read_format_raw.bufr.uu
> > Modified:
> >   head/contrib/libarchive/NEWS
> >   head/contrib/libarchive/libarchive/archive_acl.c
> >   head/contrib/libarchive/libarchive/archive_entry.c
> >   head/contrib/libarchive/libarchive/archive_entry.h
> >   head/contrib/libarchive/libarchive/archive_entry_acl.3
> >   head/contrib/libarchive/libarchive/archive_read_disk_entry_from_file.c
> >   head/contrib/libarchive/libarchive/archive_read_support_filter_xz.c
> >   head/contrib/libarchive/libarchive/archive_read_support_format_tar.c
> >   head/contrib/libarchive/libarchive/archive_read_support_format_xar.c
> >   head/contrib/libarchive/libarchive/archive_write_disk_posix.c
> >   head/contrib/libarchive/libarchive/test/test_compat_gtar.c
> >   head/contrib/libarchive/libarchive/test/test_read_format_raw.c
> >   head/contrib/libarchive/libarchive/test/test_sparse_basic.c
> >   head/contrib/libarchive/tar/test/test_symlink_dir.c
> >   head/lib/libarchive/tests/Makefile
> > Directory Properties:
> >   head/contrib/libarchive/   (props changed)
> > 
> [...]
> > Modified: head/contrib/libarchive/libarchive/archive_read_support_format_ta
> r.
> > c
> > ===========================================================================
> ==
> > =
> > --- head/contrib/libarchive/libarchive/archive_read_support_format_tar.c
> > 	Tue Nov 29 21:53:16 2016	(r309299)
> > +++ head/contrib/libarchive/libarchive/archive_read_support_format_tar.c
> > 	Tue Nov 29 22:14:42 2016	(r309300)
> > @@ -294,6 +294,46 @@ archive_read_format_tar_cleanup(struct a
> >  	return (ARCHIVE_OK);
> >  }
> >  
> > +static int
> > +validate_number_field(const char* p_field, size_t i_size)
> > +{
> > +	unsigned char marker = (unsigned char)p_field[0];
> > +	/* octal? */
> > +	if ((marker >= '0' && marker <= '7') || marker == ' ') {
> > +		size_t i = 0;
> > +		int octal_found = 0;
> > +		for (i = 0; i < i_size; ++i) {
> > +			switch (p_field[i])
> > +			{
> > +			case ' ': /* skip any leading spaces and trailing space
> > */
> > +				if (octal_found == 0 || i == i_size - 1) {
> > +					continue;
> > +				}
> > +				break;
> > +			case '\0': /* null is allowed only at the end */
> > +				if (i != i_size - 1) {
> > +					return 0;
> > +				}
> > +				break;
> > +			/* rest must be octal digits */
> > +			case '0': case '1': case '2': case '3':
> > +			case '4': case '5': case '6': case '7':
> > +				++octal_found;
> > +				break;
> > +			}
> > +		}
> > +		return octal_found > 0;
> > +	}
> > +	/* base 256 (i.e. binary number) */
> > +	else if (marker == 128 || marker == 255 || marker == 0) {
> > +		/* nothing to check */
> > +		return 1;
> > +	}
> > +	/* not a number field */
> > +	else {
> > +		return 0;
> > +	}
> > +}
> >  
> >  static int
> >  archive_read_format_tar_bid(struct archive_read *a, int best_bid)
> > @@ -346,23 +386,23 @@ archive_read_format_tar_bid(struct archi
> >  		return (0);
> >  	bid += 2;  /* 6 bits of variation in an 8-bit field leaves 2 bits. */
> >  
> > -	/* Sanity check: Look at first byte of mode field. */
> > -	switch (255 & (unsigned)header->mode[0]) {
> > -	case 0: case 255:
> > -		/* Base-256 value: No further verification possible! */
> > -		break;
> > -	case ' ': /* Not recommended, but not illegal, either. */
> > -		break;
> > -	case '0': case '1': case '2': case '3':
> > -	case '4': case '5': case '6': case '7':
> > -		/* Octal Value. */
> > -		/* TODO: Check format of remainder of this field. */
> > -		break;
> > -	default:
> > -		/* Not a valid mode; bail out here. */
> > -		return (0);
> > +	/*
> > +	 * Check format of mode/uid/gid/mtime/size/rdevmajor/rdevminor fields.
> > +	 * These are usually octal numbers but GNU tar encodes "big" values as
> > +	 * base256 and leading zeroes are sometimes replaced by spaces.
> > +	 * Even the null terminator is sometimes omitted. Anyway, must be check
> > ed
> > +	 * to avoid false positives.
> > +	 */
> > +	if (bid > 0 &&
> > +		(validate_number_field(header->mode, sizeof(header->mode)) == 0
> >  ||
> > +		 validate_number_field(header->uid, sizeof(header->uid)) == 0 |
> > |
> > +		 validate_number_field(header->gid, sizeof(header->gid)) == 0 |
> > |
> > +		 validate_number_field(header->mtime, sizeof(header->mtime)) ==
> >  0 ||
> > +		 validate_number_field(header->size, sizeof(header->size)) == 0
> >  ||
> > +		 validate_number_field(header->rdevmajor, sizeof(header->rdevma
> > jor)) == 0 ||
> > +		 validate_number_field(header->rdevminor, sizeof(header->rdevmi
> > nor)) == 0)) {
> > +			bid = 0;
> >  	}
> > -	/* TODO: Sanity test uid/gid/size/mtime/rdevmajor/rdevminor fields. */
> >  
> >  	return (bid);
> >  }
> > 
> 
> Hi,
> 
> This broke extract of older tarballs and compatibility with Perl
> Archive::Tar. You can test this by trying to extract ports/net/tcpview.
> 
> The following patch fixes it:
> 
> https://github.com/libarchive/libarchive/commit/2d2b3e928605f795515b03f060fd6
> 38c265b0778#diff-845deb76aa98ded5cb2860ded3e19dfb
> 
> The relevant part of the patch follows:
> 
> diff --git a/libarchive/archive_read_support_format_tar.c b/libarchive/archiv
> e_read_support_format_tar.c
> index 0ee511e..b977cb7 100644
> --- libarchive/archive_read_support_format_tar.c
> +++ libarchive/archive_read_support_format_tar.c
> @@ -294,8 +294,14 @@ archive_read_format_tar_cleanup(struct archive_read *a)
>  	return (ARCHIVE_OK);
>  }
>  
> +/*
> + * Validate number field
> + *
> + * Flags:
> + * 1 - allow double \0 at field end
> + */
>  static int
> -validate_number_field(const char* p_field, size_t i_size)
> +validate_number_field(const char* p_field, size_t i_size, int flags)
>  {
>  	unsigned char marker = (unsigned char)p_field[0];
>  	/* octal? */
> @@ -305,14 +311,24 @@ validate_number_field(const char* p_field, size_t i_siz
> e)
>  		for (i = 0; i < i_size; ++i) {
>  			switch (p_field[i])
>  			{
> -			case ' ': /* skip any leading spaces and trailing space
> */
> +			case ' ':
> +				/* skip any leading spaces and trailing space *
> /
>  				if (octal_found == 0 || i == i_size - 1) {
>  					continue;
>  				}
>  				break;
> -			case '\0': /* null is allowed only at the end */
> +			case '\0':
> +				/*
> +				 * null should be allowed only at the end
> +				 *
> +				 * Perl Archive::Tar terminates some fields
> +				 * with two nulls. We must allow this to stay
> +				 * compatible.
> +				 */
>  				if (i != i_size - 1) {
> -					return 0;
> +					if (((flags & 1) == 0)
> +					    || i != i_size - 2)
> +						return 0;
>  				}
>  				break;
>  			/* rest must be octal digits */
> @@ -390,18 +406,25 @@ archive_read_format_tar_bid(struct archive_read *a, int
>  best_bid)
>  	 * Check format of mode/uid/gid/mtime/size/rdevmajor/rdevminor fields.
>  	 * These are usually octal numbers but GNU tar encodes "big" values as
>  	 * base256 and leading zeroes are sometimes replaced by spaces.
> -	 * Even the null terminator is sometimes omitted. Anyway, must be check
> ed
> -	 * to avoid false positives.
> +	 * Even the null terminator is sometimes omitted. Anyway, must be
> +	 * checked to avoid false positives.
> +	 *
> +	 * Perl Archive::Tar does not follow the spec and terminates mode, uid,
> +	 * gid, rdevmajor and rdevminor with a double \0. For compatibility
> +	 * reasons we allow this deviation.
>  	 */
> -	if (bid > 0 &&
> -		(validate_number_field(header->mode, sizeof(header->mode)) == 0
>  ||
> -		 validate_number_field(header->uid, sizeof(header->uid)) == 0 |
> |
> -		 validate_number_field(header->gid, sizeof(header->gid)) == 0 |
> |
> -		 validate_number_field(header->mtime, sizeof(header->mtime)) ==
>  0 ||
> -		 validate_number_field(header->size, sizeof(header->size)) == 0
>  ||
> -		 validate_number_field(header->rdevmajor, sizeof(header->rdevma
> jor)) == 0 ||
> -		 validate_number_field(header->rdevminor, sizeof(header->rdevmi
> nor)) == 0)) {
> -			bid = 0;
> +	if (bid > 0 && (
> +	    validate_number_field(header->mode, sizeof(header->mode), 1) == 0
> +	    || validate_number_field(header->uid, sizeof(header->uid), 1) == 0
> +	    || validate_number_field(header->gid, sizeof(header->gid), 1) == 0 
> +	    || validate_number_field(header->mtime, sizeof(header->mtime),
> +	    0) == 0
> +	    || validate_number_field(header->size, sizeof(header->size), 0) == 
> 0
> +	    || validate_number_field(header->rdevmajor,
> +	    sizeof(header->rdevmajor), 1) == 0
> +	    || validate_number_field(header->rdevminor,
> +	    sizeof(header->rdevminor), 1) == 0)) {
> +		bid = 0;
>  	}
>  
>  	return (bid);
> 
> Updating to git 2d2b3e928605f795515b03f060fd638c265b0778 or later probably
> makes the most sense.

Sorry for the spam. I'm a day out of date. :(


-- 
Cheers,
Cy Schubert <Cy.Schubert@cschubert.com>
FreeBSD UNIX:  <cy@FreeBSD.org>   Web:  http://www.FreeBSD.org

	The need of the many outweighs the greed of the few.





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