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Remove unneeded checks for prelen.

Browse source 
In order to determine the type of a compressed file, we have to read
in the first four bytes which may also be important for decompression
purposes, to do that we would pass the buffer that we have already
read in, along with the size of it.

Rename header1 to fourbytes to make that explicit, and remove all
checks for prelen.

Reported by:	cem
Reviewed by:	cem
MFC after:	2 weeks
Differential Revision:	https://reviews.freebsd.org/D24034
This commit is contained in:
Xin LI 2020-03-14 05:57:22 +00:00
parent 81490eda60
commit a0eb385c2e
Notes: svn2git 2020-12-20 02:59:44 +00:00 
svn path=/head/; revision=358988
3 changed files with 17 additions and 22 deletions
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34
usr.bin/gzip/gzip.c
View file

@ -1443,7 +1443,7 @@ file_uncompress(char *file, char *outfile, size_t outsize)
struct stat isb, osb;
off_t size;
ssize_t rbytes;
unsigned char header1[4];
unsigned char fourbytes[4];
enum filetype method;
int fd, ofd, zfd = -1;
int error;
@ -1477,8 +1477,8 @@ file_uncompress(char *file, char *outfile, size_t outsize)
goto lose;
}
rbytes = read(fd, header1, sizeof header1);
if (rbytes != sizeof header1) {
rbytes = read(fd, fourbytes, sizeof fourbytes);
if (rbytes != sizeof fourbytes) {
/* we don't want to fail here. */
#ifndef SMALL
if (fflag)
@ -1492,7 +1492,7 @@ file_uncompress(char *file, char *outfile, size_t outsize)
}
infile_newdata(rbytes);
method = file_gettype(header1);
method = file_gettype(fourbytes);
#ifndef SMALL
if (fflag == 0 && method == FT_UNKNOWN) {
maybe_warnx("%s: not in gzip format", file);
@ -1516,7 +1516,7 @@ file_uncompress(char *file, char *outfile, size_t outsize)
infile_newdata(rv);
timestamp = le32dec(&ts[0]);
if (header1[3] & ORIG_NAME) {
if (fourbytes[3] & ORIG_NAME) {
rbytes = pread(fd, name, sizeof(name) - 1, GZIP_ORIGNAME);
if (rbytes < 0) {
maybe_warn("can't read %s", file);
@ -1818,7 +1818,7 @@ static void
handle_stdin(void)
{
struct stat isb;
unsigned char header1[4];
unsigned char fourbytes[4];
size_t in_size;
off_t usize, gsize;
enum filetype method;
@ -1849,16 +1849,16 @@ handle_stdin(void)
goto out;
}
bytes_read = read_retry(STDIN_FILENO, header1, sizeof header1);
bytes_read = read_retry(STDIN_FILENO, fourbytes, sizeof fourbytes);
if (bytes_read == -1) {
maybe_warn("can't read stdin");
goto out;
} else if (bytes_read != sizeof(header1)) {
} else if (bytes_read != sizeof(fourbytes)) {
maybe_warnx("(stdin): unexpected end of file");
goto out;
}
method = file_gettype(header1);
method = file_gettype(fourbytes);
switch (method) {
default:
#ifndef SMALL
@ -1866,17 +1866,17 @@ handle_stdin(void)
maybe_warnx("unknown compression format");
goto out;
}
usize = cat_fd(header1, sizeof header1, &gsize, STDIN_FILENO);
usize = cat_fd(fourbytes, sizeof fourbytes, &gsize, STDIN_FILENO);
break;
#endif
case FT_GZIP:
usize = gz_uncompress(STDIN_FILENO, STDOUT_FILENO,
(char *)header1, sizeof header1, &gsize, "(stdin)");
(char *)fourbytes, sizeof fourbytes, &gsize, "(stdin)");
break;
#ifndef NO_BZIP2_SUPPORT
case FT_BZIP2:
usize = unbzip2(STDIN_FILENO, STDOUT_FILENO,
(char *)header1, sizeof header1, &gsize);
(char *)fourbytes, sizeof fourbytes, &gsize);
break;
#endif
#ifndef NO_COMPRESS_SUPPORT
@ -1886,27 +1886,27 @@ handle_stdin(void)
goto out;
}
usize = zuncompress(in, stdout, (char *)header1,
sizeof header1, &gsize);
usize = zuncompress(in, stdout, (char *)fourbytes,
sizeof fourbytes, &gsize);
fclose(in);
break;
#endif
#ifndef NO_PACK_SUPPORT
case FT_PACK:
usize = unpack(STDIN_FILENO, STDOUT_FILENO,
(char *)header1, sizeof header1, &gsize);
(char *)fourbytes, sizeof fourbytes, &gsize);
break;
#endif
#ifndef NO_XZ_SUPPORT
case FT_XZ:
usize = unxz(STDIN_FILENO, STDOUT_FILENO,
(char *)header1, sizeof header1, &gsize);
(char *)fourbytes, sizeof fourbytes, &gsize);
break;
#endif
#ifndef NO_LZ_SUPPORT
case FT_LZ:
usize = unlz(STDIN_FILENO, STDOUT_FILENO,
(char *)header1, sizeof header1, &gsize);
(char *)fourbytes, sizeof fourbytes, &gsize);
break;
#endif
}

2
usr.bin/gzip/unlz.c
View file

@ -618,8 +618,6 @@ unlz(int fin, int fout, char *pre, size_t prelen, off_t *bytes_in)
char header[HDR_SIZE];
if (prelen > sizeof(header))
return -1;
if (pre && prelen)
memcpy(header, pre, prelen);

3
usr.bin/gzip/unpack.c
View file

@ -156,9 +156,6 @@ unpack_parse_header(int in, int out, char *pre, size_t prelen, off_t *bytes_in,
ssize_t bytesread; /* Bytes read from the file */
int i, j, thisbyte;
if (prelen > sizeof hdr)
maybe_err("prelen too long");
/* Prepend the header buffer if we already read some data */
if (prelen != 0)
memcpy(hdr, pre, prelen);