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-rw-r--r--gnu/packages/patches/unzip-zipbomb-part2.patch349
1 files changed, 349 insertions, 0 deletions
diff --git a/gnu/packages/patches/unzip-zipbomb-part2.patch b/gnu/packages/patches/unzip-zipbomb-part2.patch
new file mode 100644
index 0000000000..903c845763
--- /dev/null
+++ b/gnu/packages/patches/unzip-zipbomb-part2.patch
@@ -0,0 +1,349 @@
+From 47b3ceae397d21bf822bc2ac73052a4b1daf8e1c Mon Sep 17 00:00:00 2001
+From: Mark Adler <madler@alumni.caltech.edu>
+Date: Tue, 11 Jun 2019 22:01:18 -0700
+Subject: [PATCH] Detect and reject a zip bomb using overlapped entries.
+
+This detects an invalid zip file that has at least one entry that
+overlaps with another entry or with the central directory to the
+end of the file. A Fifield zip bomb uses overlapped local entries
+to vastly increase the potential inflation ratio. Such an invalid
+zip file is rejected.
+
+See https://www.bamsoftware.com/hacks/zipbomb/ for David Fifield's
+analysis, construction, and examples of such zip bombs.
+
+The detection maintains a list of covered spans of the zip files
+so far, where the central directory to the end of the file and any
+bytes preceding the first entry at zip file offset zero are
+considered covered initially. Then as each entry is decompressed
+or tested, it is considered covered. When a new entry is about to
+be processed, its initial offset is checked to see if it is
+contained by a covered span. If so, the zip file is rejected as
+invalid.
+
+This commit depends on a preceding commit: "Fix bug in
+undefer_input() that misplaced the input state."
+---
+ extract.c | 190 +++++++++++++++++++++++++++++++++++++++++++++++++++++-
+ globals.c | 1 +
+ globals.h | 3 +
+ process.c | 11 ++++
+ unzip.h | 1 +
+ 5 files changed, 205 insertions(+), 1 deletion(-)
+
+diff --git a/extract.c b/extract.c
+index 1acd769..0973a33 100644
+--- a/extract.c
++++ b/extract.c
+@@ -319,6 +319,125 @@ static ZCONST char Far UnsupportedExtraField[] =
+ "\nerror: unsupported extra-field compression type (%u)--skipping\n";
+ static ZCONST char Far BadExtraFieldCRC[] =
+ "error [%s]: bad extra-field CRC %08lx (should be %08lx)\n";
++static ZCONST char Far NotEnoughMemCover[] =
++ "error: not enough memory for bomb detection\n";
++static ZCONST char Far OverlappedComponents[] =
++ "error: invalid zip file with overlapped components (possible zip bomb)\n";
++
++
++
++
++
++/* A growable list of spans. */
++typedef zoff_t bound_t;
++typedef struct {
++ bound_t beg; /* start of the span */
++ bound_t end; /* one past the end of the span */
++} span_t;
++typedef struct {
++ span_t *span; /* allocated, distinct, and sorted list of spans */
++ size_t num; /* number of spans in the list */
++ size_t max; /* allocated number of spans (num <= max) */
++} cover_t;
++
++/*
++ * Return the index of the first span in cover whose beg is greater than val.
++ * If there is no such span, then cover->num is returned.
++ */
++static size_t cover_find(cover, val)
++ cover_t *cover;
++ bound_t val;
++{
++ size_t lo = 0, hi = cover->num;
++ while (lo < hi) {
++ size_t mid = (lo + hi) >> 1;
++ if (val < cover->span[mid].beg)
++ hi = mid;
++ else
++ lo = mid + 1;
++ }
++ return hi;
++}
++
++/* Return true if val lies within any one of the spans in cover. */
++static int cover_within(cover, val)
++ cover_t *cover;
++ bound_t val;
++{
++ size_t pos = cover_find(cover, val);
++ return pos > 0 && val < cover->span[pos - 1].end;
++}
++
++/*
++ * Add a new span to the list, but only if the new span does not overlap any
++ * spans already in the list. The new span covers the values beg..end-1. beg
++ * must be less than end.
++ *
++ * Keep the list sorted and merge adjacent spans. Grow the allocated space for
++ * the list as needed. On success, 0 is returned. If the new span overlaps any
++ * existing spans, then 1 is returned and the new span is not added to the
++ * list. If the new span is invalid because beg is greater than or equal to
++ * end, then -1 is returned. If the list needs to be grown but the memory
++ * allocation fails, then -2 is returned.
++ */
++static int cover_add(cover, beg, end)
++ cover_t *cover;
++ bound_t beg;
++ bound_t end;
++{
++ size_t pos;
++ int prec, foll;
++
++ if (beg >= end)
++ /* The new span is invalid. */
++ return -1;
++
++ /* Find where the new span should go, and make sure that it does not
++ overlap with any existing spans. */
++ pos = cover_find(cover, beg);
++ if ((pos > 0 && beg < cover->span[pos - 1].end) ||
++ (pos < cover->num && end > cover->span[pos].beg))
++ return 1;
++
++ /* Check for adjacencies. */
++ prec = pos > 0 && beg == cover->span[pos - 1].end;
++ foll = pos < cover->num && end == cover->span[pos].beg;
++ if (prec && foll) {
++ /* The new span connects the preceding and following spans. Merge the
++ following span into the preceding span, and delete the following
++ span. */
++ cover->span[pos - 1].end = cover->span[pos].end;
++ cover->num--;
++ memmove(cover->span + pos, cover->span + pos + 1,
++ (cover->num - pos) * sizeof(span_t));
++ }
++ else if (prec)
++ /* The new span is adjacent only to the preceding span. Extend the end
++ of the preceding span. */
++ cover->span[pos - 1].end = end;
++ else if (foll)
++ /* The new span is adjacent only to the following span. Extend the
++ beginning of the following span. */
++ cover->span[pos].beg = beg;
++ else {
++ /* The new span has gaps between both the preceding and the following
++ spans. Assure that there is room and insert the span. */
++ if (cover->num == cover->max) {
++ size_t max = cover->max == 0 ? 16 : cover->max << 1;
++ span_t *span = realloc(cover->span, max * sizeof(span_t));
++ if (span == NULL)
++ return -2;
++ cover->span = span;
++ cover->max = max;
++ }
++ memmove(cover->span + pos + 1, cover->span + pos,
++ (cover->num - pos) * sizeof(span_t));
++ cover->num++;
++ cover->span[pos].beg = beg;
++ cover->span[pos].end = end;
++ }
++ return 0;
++}
+
+
+
+@@ -374,6 +493,29 @@ int extract_or_test_files(__G) /* return PK-type error code */
+ }
+ #endif /* !SFX || SFX_EXDIR */
+
++ /* One more: initialize cover structure for bomb detection. Start with a
++ span that covers the central directory though the end of the file. */
++ if (G.cover == NULL) {
++ G.cover = malloc(sizeof(cover_t));
++ if (G.cover == NULL) {
++ Info(slide, 0x401, ((char *)slide,
++ LoadFarString(NotEnoughMemCover)));
++ return PK_MEM;
++ }
++ ((cover_t *)G.cover)->span = NULL;
++ ((cover_t *)G.cover)->max = 0;
++ }
++ ((cover_t *)G.cover)->num = 0;
++ if ((G.extra_bytes != 0 &&
++ cover_add((cover_t *)G.cover, 0, G.extra_bytes) != 0) ||
++ cover_add((cover_t *)G.cover,
++ G.extra_bytes + G.ecrec.offset_start_central_directory,
++ G.ziplen) != 0) {
++ Info(slide, 0x401, ((char *)slide,
++ LoadFarString(NotEnoughMemCover)));
++ return PK_MEM;
++ }
++
+ /*---------------------------------------------------------------------------
+ The basic idea of this function is as follows. Since the central di-
+ rectory lies at the end of the zipfile and the member files lie at the
+@@ -591,7 +733,8 @@ int extract_or_test_files(__G) /* return PK-type error code */
+ if (error > error_in_archive)
+ error_in_archive = error;
+ /* ...and keep going (unless disk full or user break) */
+- if (G.disk_full > 1 || error_in_archive == IZ_CTRLC) {
++ if (G.disk_full > 1 || error_in_archive == IZ_CTRLC ||
++ error == PK_BOMB) {
+ /* clear reached_end to signal premature stop ... */
+ reached_end = FALSE;
+ /* ... and cancel scanning the central directory */
+@@ -1060,6 +1203,11 @@ static int extract_or_test_entrylist(__G__ numchunk,
+
+ /* seek_zipf(__G__ pInfo->offset); */
+ request = G.pInfo->offset + G.extra_bytes;
++ if (cover_within((cover_t *)G.cover, request)) {
++ Info(slide, 0x401, ((char *)slide,
++ LoadFarString(OverlappedComponents)));
++ return PK_BOMB;
++ }
+ inbuf_offset = request % INBUFSIZ;
+ bufstart = request - inbuf_offset;
+
+@@ -1591,6 +1739,18 @@ static int extract_or_test_entrylist(__G__ numchunk,
+ return IZ_CTRLC; /* cancel operation by user request */
+ }
+ #endif
++ error = cover_add((cover_t *)G.cover, request,
++ G.cur_zipfile_bufstart + (G.inptr - G.inbuf));
++ if (error < 0) {
++ Info(slide, 0x401, ((char *)slide,
++ LoadFarString(NotEnoughMemCover)));
++ return PK_MEM;
++ }
++ if (error != 0) {
++ Info(slide, 0x401, ((char *)slide,
++ LoadFarString(OverlappedComponents)));
++ return PK_BOMB;
++ }
+ #ifdef MACOS /* MacOS is no preemptive OS, thus call event-handling by hand */
+ UserStop();
+ #endif
+@@ -1992,6 +2152,34 @@ static int extract_or_test_member(__G) /* return PK-type error code */
+ }
+
+ undefer_input(__G);
++
++ if ((G.lrec.general_purpose_bit_flag & 8) != 0) {
++ /* skip over data descriptor (harder than it sounds, due to signature
++ * ambiguity)
++ */
++# define SIG 0x08074b50
++# define LOW 0xffffffff
++ uch buf[12];
++ unsigned shy = 12 - readbuf((char *)buf, 12);
++ ulg crc = shy ? 0 : makelong(buf);
++ ulg clen = shy ? 0 : makelong(buf + 4);
++ ulg ulen = shy ? 0 : makelong(buf + 8); /* or high clen if ZIP64 */
++ if (crc == SIG && /* if not SIG, no signature */
++ (G.lrec.crc32 != SIG || /* if not SIG, have signature */
++ (clen == SIG && /* if not SIG, no signature */
++ ((G.lrec.csize & LOW) != SIG || /* if not SIG, have signature */
++ (ulen == SIG && /* if not SIG, no signature */
++ (G.zip64 ? G.lrec.csize >> 32 : G.lrec.ucsize) != SIG
++ /* if not SIG, have signature */
++ )))))
++ /* skip four more bytes to account for signature */
++ shy += 4 - readbuf((char *)buf, 4);
++ if (G.zip64)
++ shy += 8 - readbuf((char *)buf, 8); /* skip eight more for ZIP64 */
++ if (shy)
++ error = PK_ERR;
++ }
++
+ return error;
+
+ } /* end function extract_or_test_member() */
+diff --git a/globals.c b/globals.c
+index fa8cca5..1e0f608 100644
+--- a/globals.c
++++ b/globals.c
+@@ -181,6 +181,7 @@ Uz_Globs *globalsCtor()
+ # if (!defined(NO_TIMESTAMPS))
+ uO.D_flag=1; /* default to '-D', no restoration of dir timestamps */
+ # endif
++ G.cover = NULL; /* not allocated yet */
+ #endif
+
+ uO.lflag=(-1);
+diff --git a/globals.h b/globals.h
+index 11b7215..2bdcdeb 100644
+--- a/globals.h
++++ b/globals.h
+@@ -260,12 +260,15 @@ typedef struct Globals {
+ ecdir_rec ecrec; /* used in unzip.c, extract.c */
+ z_stat statbuf; /* used by main, mapname, check_for_newer */
+
++ int zip64; /* true if Zip64 info in extra field */
++
+ int mem_mode;
+ uch *outbufptr; /* extract.c static */
+ ulg outsize; /* extract.c static */
+ int reported_backslash; /* extract.c static */
+ int disk_full;
+ int newfile;
++ void **cover; /* used in extract.c for bomb detection */
+
+ int didCRlast; /* fileio static */
+ ulg numlines; /* fileio static: number of lines printed */
+diff --git a/process.c b/process.c
+index 1e9a1e1..d2e4dc3 100644
+--- a/process.c
++++ b/process.c
+@@ -637,6 +637,13 @@ void free_G_buffers(__G) /* releases all memory allocated in global vars */
+ }
+ #endif
+
++ /* Free the cover span list and the cover structure. */
++ if (G.cover != NULL) {
++ free(*(G.cover));
++ free(G.cover);
++ G.cover = NULL;
++ }
++
+ } /* end function free_G_buffers() */
+
+
+@@ -1890,6 +1897,8 @@ int getZip64Data(__G__ ef_buf, ef_len)
+ #define Z64FLGS 0xffff
+ #define Z64FLGL 0xffffffff
+
++ G.zip64 = FALSE;
++
+ if (ef_len == 0 || ef_buf == NULL)
+ return PK_COOL;
+
+@@ -1927,6 +1936,8 @@ int getZip64Data(__G__ ef_buf, ef_len)
+ #if 0
+ break; /* Expect only one EF_PKSZ64 block. */
+ #endif /* 0 */
++
++ G.zip64 = TRUE;
+ }
+
+ /* Skip this extra field block. */
+diff --git a/unzip.h b/unzip.h
+index 5b2a326..ed24a5b 100644
+--- a/unzip.h
++++ b/unzip.h
+@@ -645,6 +645,7 @@ typedef struct _Uzp_cdir_Rec {
+ #define PK_NOZIP 9 /* zipfile not found */
+ #define PK_PARAM 10 /* bad or illegal parameters specified */
+ #define PK_FIND 11 /* no files found */
++#define PK_BOMB 12 /* likely zip bomb */
+ #define PK_DISK 50 /* disk full */
+ #define PK_EOF 51 /* unexpected EOF */
+
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