https://github.com/git/git
Revision 34ace8bad02bb14ecc5b631f7e3daaa7a9bba7d9 authored by Patrick Steinhardt on 01 December 2022, 14:45:27 UTC, committed by Junio C Hamano on 05 December 2022, 06:14:16 UTC
It is possible to trigger an integer overflow when parsing attribute names when there are more than 2^31 of them for a single pattern. This can either lead to us dying due to trying to request too many bytes: blob=$(perl -e 'print "f" . " a=" x 2147483649' | git hash-object -w --stdin) git update-index --add --cacheinfo 100644,$blob,.gitattributes git attr-check --all file ================================================================= ==1022==ERROR: AddressSanitizer: requested allocation size 0xfffffff800000032 (0xfffffff800001038 after adjustments for alignment, red zones etc.) exceeds maximum supported size of 0x10000000000 (thread T0) #0 0x7fd3efabf411 in __interceptor_calloc /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 #1 0x5563a0a1e3d3 in xcalloc wrapper.c:150 #2 0x5563a058d005 in parse_attr_line attr.c:384 #3 0x5563a058e661 in handle_attr_line attr.c:660 #4 0x5563a058eddb in read_attr_from_index attr.c:769 #5 0x5563a058ef12 in read_attr attr.c:797 #6 0x5563a058f24c in bootstrap_attr_stack attr.c:867 #7 0x5563a058f4a3 in prepare_attr_stack attr.c:902 #8 0x5563a05905da in collect_some_attrs attr.c:1097 #9 0x5563a059093d in git_all_attrs attr.c:1128 #10 0x5563a02f636e in check_attr builtin/check-attr.c:67 #11 0x5563a02f6c12 in cmd_check_attr builtin/check-attr.c:183 #12 0x5563a02aa993 in run_builtin git.c:466 #13 0x5563a02ab397 in handle_builtin git.c:721 #14 0x5563a02abb2b in run_argv git.c:788 #15 0x5563a02ac991 in cmd_main git.c:926 #16 0x5563a05432bd in main common-main.c:57 #17 0x7fd3ef82228f (/usr/lib/libc.so.6+0x2328f) ==1022==HINT: if you don't care about these errors you may set allocator_may_return_null=1 SUMMARY: AddressSanitizer: allocation-size-too-big /usr/src/debug/gcc/libsanitizer/asan/asan_malloc_linux.cpp:77 in __interceptor_calloc ==1022==ABORTING Or, much worse, it can lead to an out-of-bounds write because we underallocate and then memcpy(3P) into an array: perl -e ' print "A " . "\rh="x2000000000; print "\rh="x2000000000; print "\rh="x294967294 . "\n" ' >.gitattributes git add .gitattributes git commit -am "evil attributes" $ git clone --quiet /path/to/repo ================================================================= ==15062==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x602000002550 at pc 0x5555559884d5 bp 0x7fffffffbc60 sp 0x7fffffffbc58 WRITE of size 8 at 0x602000002550 thread T0 #0 0x5555559884d4 in parse_attr_line attr.c:393 #1 0x5555559884d4 in handle_attr_line attr.c:660 #2 0x555555988902 in read_attr_from_index attr.c:784 #3 0x555555988902 in read_attr_from_index attr.c:747 #4 0x555555988a1d in read_attr attr.c:800 #5 0x555555989b0c in bootstrap_attr_stack attr.c:882 #6 0x555555989b0c in prepare_attr_stack attr.c:917 #7 0x555555989b0c in collect_some_attrs attr.c:1112 #8 0x55555598b141 in git_check_attr attr.c:1126 #9 0x555555a13004 in convert_attrs convert.c:1311 #10 0x555555a95e04 in checkout_entry_ca entry.c:553 #11 0x555555d58bf6 in checkout_entry entry.h:42 #12 0x555555d58bf6 in check_updates unpack-trees.c:480 #13 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #14 0x555555785ab7 in checkout builtin/clone.c:724 #15 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #16 0x55555572443c in run_builtin git.c:466 #17 0x55555572443c in handle_builtin git.c:721 #18 0x555555727872 in run_argv git.c:788 #19 0x555555727872 in cmd_main git.c:926 #20 0x555555721fa0 in main common-main.c:57 #21 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 #22 0x555555723f39 in _start (git+0x1cff39) 0x602000002552 is located 0 bytes to the right of 2-byte region [0x602000002550,0x602000002552) allocated by thread T0 here: #0 0x7ffff768c037 in __interceptor_calloc ../../../../src/libsanitizer/asan/asan_malloc_linux.cpp:154 #1 0x555555d7fff7 in xcalloc wrapper.c:150 #2 0x55555598815f in parse_attr_line attr.c:384 #3 0x55555598815f in handle_attr_line attr.c:660 #4 0x555555988902 in read_attr_from_index attr.c:784 #5 0x555555988902 in read_attr_from_index attr.c:747 #6 0x555555988a1d in read_attr attr.c:800 #7 0x555555989b0c in bootstrap_attr_stack attr.c:882 #8 0x555555989b0c in prepare_attr_stack attr.c:917 #9 0x555555989b0c in collect_some_attrs attr.c:1112 #10 0x55555598b141 in git_check_attr attr.c:1126 #11 0x555555a13004 in convert_attrs convert.c:1311 #12 0x555555a95e04 in checkout_entry_ca entry.c:553 #13 0x555555d58bf6 in checkout_entry entry.h:42 #14 0x555555d58bf6 in check_updates unpack-trees.c:480 #15 0x555555d5eb55 in unpack_trees unpack-trees.c:2040 #16 0x555555785ab7 in checkout builtin/clone.c:724 #17 0x555555785ab7 in cmd_clone builtin/clone.c:1384 #18 0x55555572443c in run_builtin git.c:466 #19 0x55555572443c in handle_builtin git.c:721 #20 0x555555727872 in run_argv git.c:788 #21 0x555555727872 in cmd_main git.c:926 #22 0x555555721fa0 in main common-main.c:57 #23 0x7ffff73f1d09 in __libc_start_main ../csu/libc-start.c:308 SUMMARY: AddressSanitizer: heap-buffer-overflow attr.c:393 in parse_attr_line Shadow bytes around the buggy address: 0x0c047fff8450: fa fa 00 02 fa fa 00 07 fa fa fd fd fa fa 00 00 0x0c047fff8460: fa fa 02 fa fa fa fd fd fa fa 00 06 fa fa 05 fa 0x0c047fff8470: fa fa fd fd fa fa 00 02 fa fa 06 fa fa fa 05 fa 0x0c047fff8480: fa fa 07 fa fa fa fd fd fa fa 00 01 fa fa 00 02 0x0c047fff8490: fa fa 00 03 fa fa 00 fa fa fa 00 01 fa fa 00 03 =>0x0c047fff84a0: fa fa 00 01 fa fa 00 02 fa fa[02]fa fa fa fa fa 0x0c047fff84b0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84c0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84d0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84e0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa 0x0c047fff84f0: fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa fa Shadow byte legend (one shadow byte represents 8 application bytes): Addressable: 00 Partially addressable: 01 02 03 04 05 06 07 Heap left redzone: fa Freed heap region: fd Stack left redzone: f1 Stack mid redzone: f2 Stack right redzone: f3 Stack after return: f5 Stack use after scope: f8 Global redzone: f9 Global init order: f6 Poisoned by user: f7 Container overflow: fc Array cookie: ac Intra object redzone: bb ASan internal: fe Left alloca redzone: ca Right alloca redzone: cb Shadow gap: cc ==15062==ABORTING Fix this bug by using `size_t` instead to count the number of attributes so that this value cannot reasonably overflow without running out of memory before already. Reported-by: Markus Vervier <markus.vervier@x41-dsec.de> Signed-off-by: Patrick Steinhardt <ps@pks.im> Signed-off-by: Junio C Hamano <gitster@pobox.com>
1 parent 2455720
Tip revision: 34ace8bad02bb14ecc5b631f7e3daaa7a9bba7d9 authored by Patrick Steinhardt on 01 December 2022, 14:45:27 UTC
attr: fix out-of-bounds write when parsing huge number of attributes
attr: fix out-of-bounds write when parsing huge number of attributes
Tip revision: 34ace8b
notes.h
#ifndef NOTES_H
#define NOTES_H
#include "string-list.h"
struct object_id;
struct strbuf;
/*
* Function type for combining two notes annotating the same object.
*
* When adding a new note annotating the same object as an existing note, it is
* up to the caller to decide how to combine the two notes. The decision is
* made by passing in a function of the following form. The function accepts
* two object_ids -- of the existing note and the new note, respectively. The
* function then combines the notes in whatever way it sees fit, and writes the
* resulting oid into the first argument (cur_oid). A non-zero return
* value indicates failure.
*
* The two given object_ids shall both be non-NULL and different from each
* other. Either of them (but not both) may be == null_oid, which indicates an
* empty/non-existent note. If the resulting oid (cur_oid) is == null_oid,
* the note will be removed from the notes tree.
*
* The default combine_notes function (you get this when passing NULL) is
* combine_notes_concatenate(), which appends the contents of the new note to
* the contents of the existing note.
*/
typedef int (*combine_notes_fn)(struct object_id *cur_oid,
const struct object_id *new_oid);
/* Common notes combinators */
int combine_notes_concatenate(struct object_id *cur_oid,
const struct object_id *new_oid);
int combine_notes_overwrite(struct object_id *cur_oid,
const struct object_id *new_oid);
int combine_notes_ignore(struct object_id *cur_oid,
const struct object_id *new_oid);
int combine_notes_cat_sort_uniq(struct object_id *cur_oid,
const struct object_id *new_oid);
/*
* Notes tree object
*
* Encapsulates the internal notes tree structure associated with a notes ref.
* Whenever a struct notes_tree pointer is required below, you may pass NULL in
* order to use the default/internal notes tree. E.g. you only need to pass a
* non-NULL value if you need to refer to several different notes trees
* simultaneously.
*/
extern struct notes_tree {
struct int_node *root;
struct non_note *first_non_note, *prev_non_note;
char *ref;
char *update_ref;
combine_notes_fn combine_notes;
int initialized;
int dirty;
} default_notes_tree;
/*
* Return the default notes ref.
*
* The default notes ref is the notes ref that is used when notes_ref == NULL
* is passed to init_notes().
*
* This the first of the following to be defined:
* 1. The '--ref' option to 'git notes', if given
* 2. The $GIT_NOTES_REF environment variable, if set
* 3. The value of the core.notesRef config variable, if set
* 4. GIT_NOTES_DEFAULT_REF (i.e. "refs/notes/commits")
*/
const char *default_notes_ref(void);
/*
* Flags controlling behaviour of notes tree initialization
*
* Default behaviour is to initialize the notes tree from the tree object
* specified by the given (or default) notes ref.
*/
#define NOTES_INIT_EMPTY 1
/*
* By default, the notes tree is only readable, and the notes ref can be
* any treeish. The notes tree can however be made writable with this flag,
* in which case only strict ref names can be used.
*/
#define NOTES_INIT_WRITABLE 2
/*
* Initialize the given notes_tree with the notes tree structure at the given
* ref. If given ref is NULL, the value of the $GIT_NOTES_REF environment
* variable is used, and if that is missing, the default notes ref is used
* ("refs/notes/commits").
*
* If you need to re-initialize a notes_tree structure (e.g. when switching from
* one notes ref to another), you must first de-initialize the notes_tree
* structure by calling free_notes(struct notes_tree *).
*
* If you pass t == NULL, the default internal notes_tree will be initialized.
*
* The combine_notes function that is passed becomes the default combine_notes
* function for the given notes_tree. If NULL is passed, the default
* combine_notes function is combine_notes_concatenate().
*
* Precondition: The notes_tree structure is zeroed (this can be achieved with
* memset(t, 0, sizeof(struct notes_tree)))
*/
void init_notes(struct notes_tree *t, const char *notes_ref,
combine_notes_fn combine_notes, int flags);
/*
* Add the given note object to the given notes_tree structure
*
* If there already exists a note for the given object_sha1, the given
* combine_notes function is invoked to break the tie. If not given (i.e.
* combine_notes == NULL), the default combine_notes function for the given
* notes_tree is used.
*
* Passing note_sha1 == null_sha1 indicates the addition of an
* empty/non-existent note. This is a (potentially expensive) no-op unless
* there already exists a note for the given object_sha1, AND combining that
* note with the empty note (using the given combine_notes function) results
* in a new/changed note.
*
* Returns zero on success; non-zero means combine_notes failed.
*
* IMPORTANT: The changes made by add_note() to the given notes_tree structure
* are not persistent until a subsequent call to write_notes_tree() returns
* zero.
*/
int add_note(struct notes_tree *t, const struct object_id *object_oid,
const struct object_id *note_oid, combine_notes_fn combine_notes);
/*
* Remove the given note object from the given notes_tree structure
*
* IMPORTANT: The changes made by remove_note() to the given notes_tree
* structure are not persistent until a subsequent call to write_notes_tree()
* returns zero.
*
* Return 0 if a note was removed; 1 if there was no note to remove.
*/
int remove_note(struct notes_tree *t, const unsigned char *object_sha1);
/*
* Get the note object SHA1 containing the note data for the given object
*
* Return NULL if the given object has no notes.
*/
const struct object_id *get_note(struct notes_tree *t,
const struct object_id *object_oid);
/*
* Copy a note from one object to another in the given notes_tree.
*
* Returns 1 if the to_obj already has a note and 'force' is false. Otherwise,
* returns non-zero if 'force' is true, but the given combine_notes function
* failed to combine from_obj's note with to_obj's existing note.
* Returns zero on success.
*
* IMPORTANT: The changes made by copy_note() to the given notes_tree structure
* are not persistent until a subsequent call to write_notes_tree() returns
* zero.
*/
int copy_note(struct notes_tree *t,
const struct object_id *from_obj, const struct object_id *to_obj,
int force, combine_notes_fn combine_notes);
/*
* Flags controlling behaviour of for_each_note()
*
* Default behaviour of for_each_note() is to traverse every single note object
* in the given notes tree, unpacking subtree entries along the way.
* The following flags can be used to alter the default behaviour:
*
* - DONT_UNPACK_SUBTREES causes for_each_note() NOT to unpack and recurse into
* subtree entries while traversing the notes tree. This causes notes within
* those subtrees NOT to be passed to the callback. Use this flag if you
* don't want to traverse _all_ notes, but only want to traverse the parts
* of the notes tree that have already been unpacked (this includes at least
* all notes that have been added/changed).
*
* - YIELD_SUBTREES causes any subtree entries that are encountered to be
* passed to the callback, before recursing into them. Subtree entries are
* not note objects, but represent intermediate directories in the notes
* tree. When passed to the callback, subtree entries will have a trailing
* slash in their path, which the callback may use to differentiate between
* note entries and subtree entries. Note that already-unpacked subtree
* entries are not part of the notes tree, and will therefore not be yielded.
* If this flag is used together with DONT_UNPACK_SUBTREES, for_each_note()
* will yield the subtree entry, but not recurse into it.
*/
#define FOR_EACH_NOTE_DONT_UNPACK_SUBTREES 1
#define FOR_EACH_NOTE_YIELD_SUBTREES 2
/*
* Invoke the specified callback function for each note in the given notes_tree
*
* If the callback returns nonzero, the note walk is aborted, and the return
* value from the callback is returned from for_each_note(). Hence, a zero
* return value from for_each_note() indicates that all notes were walked
* successfully.
*
* IMPORTANT: The callback function is NOT allowed to change the notes tree.
* In other words, the following functions can NOT be invoked (on the current
* notes tree) from within the callback:
* - add_note()
* - remove_note()
* - copy_note()
* - free_notes()
*/
typedef int each_note_fn(const struct object_id *object_oid,
const struct object_id *note_oid, char *note_path,
void *cb_data);
int for_each_note(struct notes_tree *t, int flags, each_note_fn fn,
void *cb_data);
/*
* Write the given notes_tree structure to the object database
*
* Creates a new tree object encapsulating the current state of the given
* notes_tree, and stores its object id into the 'result' argument.
*
* Returns zero on success, non-zero on failure.
*
* IMPORTANT: Changes made to the given notes_tree are not persistent until
* this function has returned zero. Please also remember to create a
* corresponding commit object, and update the appropriate notes ref.
*/
int write_notes_tree(struct notes_tree *t, struct object_id *result);
/* Flags controlling the operation of prune */
#define NOTES_PRUNE_VERBOSE 1
#define NOTES_PRUNE_DRYRUN 2
/*
* Remove all notes annotating non-existing objects from the given notes tree
*
* All notes in the given notes_tree that are associated with objects that no
* longer exist in the database, are removed from the notes tree.
*
* IMPORTANT: The changes made by prune_notes() to the given notes_tree
* structure are not persistent until a subsequent call to write_notes_tree()
* returns zero.
*/
void prune_notes(struct notes_tree *t, int flags);
/*
* Free (and de-initialize) the given notes_tree structure
*
* IMPORTANT: Changes made to the given notes_tree since the last, successful
* call to write_notes_tree() will be lost.
*/
void free_notes(struct notes_tree *t);
struct string_list;
struct display_notes_opt {
int use_default_notes;
struct string_list extra_notes_refs;
};
/*
* Initialize a display_notes_opt to its default value.
*/
void init_display_notes(struct display_notes_opt *opt);
/*
* This family of functions enables or disables the display of notes. In
* particular, 'enable_default_display_notes' will display the default notes,
* 'enable_ref_display_notes' will display the notes ref 'ref' and
* 'disable_display_notes' will disable notes, including those added by previous
* invocations of the 'enable_*_display_notes' functions.
*
* 'show_notes' is a pointer to a boolean which will be set to 1 if notes are
* displayed, else 0. It must not be NULL.
*/
void enable_default_display_notes(struct display_notes_opt *opt, int *show_notes);
void enable_ref_display_notes(struct display_notes_opt *opt, int *show_notes,
const char *ref);
void disable_display_notes(struct display_notes_opt *opt, int *show_notes);
/*
* Load the notes machinery for displaying several notes trees.
*
* If 'opt' is not NULL, then it specifies additional settings for the
* displaying:
*
* - suppress_default_notes indicates that the notes from
* core.notesRef and notes.displayRef should not be loaded.
*
* - extra_notes_refs may contain a list of globs (in the same style
* as notes.displayRef) where notes should be loaded from.
*/
void load_display_notes(struct display_notes_opt *opt);
/*
* Append notes for the given 'object_sha1' from all trees set up by
* load_display_notes() to 'sb'.
*
* If 'raw' is false the note will be indented by 4 places and
* a 'Notes (refname):' header added.
*
* You *must* call load_display_notes() before using this function.
*/
void format_display_notes(const struct object_id *object_oid,
struct strbuf *sb, const char *output_encoding, int raw);
/*
* Load the notes tree from each ref listed in 'refs'. The output is
* an array of notes_tree*, terminated by a NULL.
*/
struct notes_tree **load_notes_trees(struct string_list *refs, int flags);
/*
* Add all refs that match 'glob' to the 'list'.
*/
void string_list_add_refs_by_glob(struct string_list *list, const char *glob);
/*
* Add all refs from a colon-separated glob list 'globs' to the end of
* 'list'. Empty components are ignored. This helper is used to
* parse GIT_NOTES_DISPLAY_REF style environment variables.
*/
void string_list_add_refs_from_colon_sep(struct string_list *list,
const char *globs);
/* Expand inplace a note ref like "foo" or "notes/foo" into "refs/notes/foo" */
void expand_notes_ref(struct strbuf *sb);
/*
* Similar to expand_notes_ref, but will check whether the ref can be located
* via get_sha1 first, and only falls back to expand_notes_ref in the case
* where get_sha1 fails.
*/
void expand_loose_notes_ref(struct strbuf *sb);
#endif
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