diff options
Diffstat (limited to 'gnu/packages/patches/unzip-zipbomb-part2.patch')
| -rw-r--r-- | gnu/packages/patches/unzip-zipbomb-part2.patch | 349 |
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 */ + |