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Merge pull request #3099 from stoeckmann/7zip_seek

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7zip: Extend support for filtered input
This commit is contained in:
Martin Matuška authored and GitHub committed 2026-06-01 09:51:32 +02:00
2 parents bb0d9dfd39 dc6f400bb7
commit 0ebc440d8e
1 file changed
+47 -15
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libarchive/archive_read_support_format_7zip.c
+47 -15
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@@ -450,9 +450,9 @@ static ssize_t read_stream(struct archive_read *, const void **, size_t,
size_t);
static int seek_pack(struct archive_read *);
static int64_t skip_stream(struct archive_read *, size_t);
static int get_data_offset(struct archive_read *, int64_t *);
static int get_data_offset(struct archive_read *, int64_t *, int);
static int get_pe_sfx_offset(struct archive_read *, int64_t *);
static int get_elf_sfx_offset(struct archive_read *, int64_t *);
static int get_elf_sfx_offset(struct archive_read *, int64_t *, int);
static int slurp_central_directory(struct archive_read *, struct _7zip *,
struct _7z_header_info *);
static int setup_decode_folder(struct archive_read *, struct _7z_folder *,
@@ -465,6 +465,7 @@ static size_t arm64_Convert(struct _7zip *, uint8_t *, size_t);
static ssize_t Bcj2_Decode(struct _7zip *, uint8_t *, size_t);
static size_t sparc_Convert(struct _7zip *, uint8_t *, size_t);
static size_t powerpc_Convert(struct _7zip *, uint8_t *, size_t);
static int64_t seek_compat(struct archive_read *, int64_t, int, int);
int
@@ -531,7 +532,7 @@ archive_read_format_7zip_has_encrypted_entries(struct archive_read *_a)
}
static int
get_data_offset(struct archive_read *a, int64_t *data_offset)
get_data_offset(struct archive_read *a, int64_t *data_offset, int compat)
{
const unsigned char *p;
int64_t offset, sfx_offset;
@@ -561,7 +562,7 @@ get_data_offset(struct archive_read *a, int64_t *data_offset)
if ((p[0] == 'M' && p[1] == 'Z'))
r = get_pe_sfx_offset(a, &sfx_offset);
else if (memcmp(p, "\x7F\x45LF", 4) == 0)
r = get_elf_sfx_offset(a, &sfx_offset);
r = get_elf_sfx_offset(a, &sfx_offset, compat);
else
r = ARCHIVE_FATAL;
if (r < ARCHIVE_WARN || sfx_offset > SFX_MAX_SEEK)
@@ -607,7 +608,7 @@ archive_read_format_7zip_bid(struct archive_read *a, int best_bid)
if (best_bid > 32)
return (-1);
if (get_data_offset(a, &data_offset) < 0)
if (get_data_offset(a, &data_offset, 0) < 0)
return (0);
return (48);
@@ -730,7 +731,7 @@ get_pe_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
}
static int
get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset, int compat)
{
int64_t r;
const char *h;
@@ -798,7 +799,7 @@ get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
/*
* Reading the section table to find strtab section
*/
if (__archive_read_seek(a, e_shoff, SEEK_SET) < 0) {
if (seek_compat(a, e_shoff, SEEK_SET, compat) < 0) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (ARCHIVE_FATAL);
}
@@ -832,7 +833,7 @@ get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
/*
* Read the STRTAB section to find the .data offset
*/
if (__archive_read_seek(a, strtab_offset, SEEK_SET) < 0) {
if (seek_compat(a, strtab_offset, SEEK_SET, compat) < 0) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (ARCHIVE_FATAL);
}
@@ -854,7 +855,7 @@ get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
/*
* Find the section with the .data name
*/
if (__archive_read_seek(a, e_shoff, SEEK_SET) < 0) {
if (seek_compat(a, e_shoff, SEEK_SET, compat) < 0) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (ARCHIVE_FATAL);
}
@@ -887,7 +888,7 @@ get_elf_sfx_offset(struct archive_read *a, int64_t *sfx_offset)
break;
}
r = __archive_read_seek(a, 0, SEEK_SET);
r = seek_compat(a, 0, SEEK_SET, compat);
if (r < 0)
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (int)r;
@@ -3269,7 +3270,7 @@ slurp_central_directory(struct archive_read *a, struct _7zip *zip,
int64_t data_offset;
int check_header_crc, r;
if (get_data_offset(a, &data_offset) < 0)
if (get_data_offset(a, &data_offset, 1) < 0)
return (ARCHIVE_FATAL);
if (__archive_read_consume(a, data_offset) < 0) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
@@ -3313,8 +3314,8 @@ slurp_central_directory(struct archive_read *a, struct _7zip *zip,
if (next_header_offset != 0) {
if (bytes_avail >= (ssize_t)next_header_offset)
__archive_read_consume(a, next_header_offset);
else if (__archive_read_seek(a,
next_header_offset + zip->seek_base, SEEK_SET) < 0) {
else if (seek_compat(a,
next_header_offset + zip->seek_base, SEEK_SET, 1) < 0) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (ARCHIVE_FATAL);
}
@@ -3653,8 +3654,8 @@ seek_pack(struct archive_read *a)
zip->si.pi.sizes[zip->pack_stream_index];
pack_offset = zip->si.pi.positions[zip->pack_stream_index];
if (zip->stream_offset != pack_offset) {
if (0 > __archive_read_seek(a, pack_offset + zip->seek_base,
SEEK_SET)) {
if (0 > seek_compat(a, pack_offset + zip->seek_base,
SEEK_SET, 1)) {
archive_set_error(&a->archive, ARCHIVE_ERRNO_MISC, "Seek error");
return (ARCHIVE_FATAL);
}
@@ -4595,3 +4596,34 @@ Bcj2_Decode(struct _7zip *zip, uint8_t *outBuf, size_t outSize)
return ((ssize_t)outPos);
}
/*
* Perform a seek to given position. If seeking is not supported,
* target position is in front of current position, and compat is requested,
* try to consume bytes until position is reached.
*/
int64_t
seek_compat(struct archive_read *a, int64_t offset, int whence, int compat)
{
int64_t ret = ARCHIVE_FAILED;
if (a->filter->can_seek)
ret = __archive_read_seek(a, offset, whence);
else if (compat) {
switch (whence) {
case SEEK_CUR:
ret = __archive_read_consume(a, offset);
break;
case SEEK_SET:
if (a->filter->position > offset)
break;
ret = __archive_read_consume(a,
offset - a->filter->position);
break;
default:
break;
}
}
return (ret);
}