https://github.com/git/git
Revision a5bb10fd5e74101e7c07da93e7c32bbe60f6173a authored by Taylor Blau on 06 April 2023, 18:07:58 UTC, committed by Johannes Schindelin on 17 April 2023, 19:15:40 UTC
When renaming (or deleting) a section of configuration, Git uses the
function `git_config_copy_or_rename_section_in_file()` to rewrite the
configuration file after applying the rename or deletion to the given
section.
To do this, Git repeatedly calls `fgets()` to read the existing
configuration data into a fixed size buffer.
When the configuration value under `old_name` exceeds the size of the
buffer, we will call `fgets()` an additional time even if there is no
newline in the configuration file, since our read length is capped at
`sizeof(buf)`.
If the first character of the buffer (after zero or more characters
satisfying `isspace()`) is a '[', Git will incorrectly treat it as
beginning a new section when the original section is being removed. In
other words, a configuration value satisfying this criteria can
incorrectly be considered as a new secftion instead of a variable in the
original section.
Avoid this issue by using a variable-width buffer in the form of a
strbuf rather than a fixed-with region on the stack. A couple of small
points worth noting:
- Using a strbuf will cause us to allocate arbitrary sizes to match
the length of each line. In practice, we don't expect any
reasonable configuration files to have lines that long, and a
bandaid will be introduced in a later patch to ensure that this is
the case.
- We are using strbuf_getwholeline() here instead of strbuf_getline()
in order to match `fgets()`'s behavior of leaving the trailing LF
character on the buffer (as well as a trailing NUL).
This could be changed later, but using strbuf_getwholeline() changes
the least about this function's implementation, so it is picked as
the safest path.
- It is temping to want to replace the loop to skip over characters
matching isspace() at the beginning of the buffer with a convenience
function like `strbuf_ltrim()`. But this is the wrong approach for a
couple of reasons:
First, it involves a potentially large and expensive `memmove()`
which we would like to avoid. Second, and more importantly, we also
*do* want to preserve those spaces to avoid changing the output of
other sections.
In all, this patch is a minimal replacement of the fixed-width buffer in
`git_config_copy_or_rename_section_in_file()` to instead use a `struct
strbuf`.
Reported-by: André Baptista <andre@ethiack.com>
Reported-by: Vítor Pinho <vitor@ethiack.com>
Helped-by: Patrick Steinhardt <ps@pks.im>
Co-authored-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Johannes Schindelin <Johannes.Schindelin@gmx.de>
Signed-off-by: Taylor Blau <me@ttaylorr.com>
1 parent 2919821
Tip revision: a5bb10fd5e74101e7c07da93e7c32bbe60f6173a authored by Taylor Blau on 06 April 2023, 18:07:58 UTC
config: avoid fixed-sized buffer when renaming/deleting a section
config: avoid fixed-sized buffer when renaming/deleting a section
Tip revision: a5bb10f
wt-status.h
#ifndef STATUS_H
#define STATUS_H
#include "string-list.h"
#include "color.h"
#include "pathspec.h"
#include "remote.h"
struct repository;
struct worktree;
enum color_wt_status {
WT_STATUS_HEADER = 0,
WT_STATUS_UPDATED,
WT_STATUS_CHANGED,
WT_STATUS_UNTRACKED,
WT_STATUS_NOBRANCH,
WT_STATUS_UNMERGED,
WT_STATUS_LOCAL_BRANCH,
WT_STATUS_REMOTE_BRANCH,
WT_STATUS_ONBRANCH,
WT_STATUS_MAXSLOT
};
enum untracked_status_type {
SHOW_NO_UNTRACKED_FILES,
SHOW_NORMAL_UNTRACKED_FILES,
SHOW_ALL_UNTRACKED_FILES
};
enum show_ignored_type {
SHOW_NO_IGNORED,
SHOW_TRADITIONAL_IGNORED,
SHOW_MATCHING_IGNORED,
};
/* from where does this commit originate */
enum commit_whence {
FROM_COMMIT, /* normal */
FROM_MERGE, /* commit came from merge */
FROM_CHERRY_PICK_SINGLE, /* commit came from cherry-pick */
FROM_CHERRY_PICK_MULTI, /* commit came from a sequence of cherry-picks */
FROM_REBASE_PICK /* commit came from a pick/reword/edit */
};
static inline int is_from_cherry_pick(enum commit_whence whence)
{
return whence == FROM_CHERRY_PICK_SINGLE ||
whence == FROM_CHERRY_PICK_MULTI;
}
static inline int is_from_rebase(enum commit_whence whence)
{
return whence == FROM_REBASE_PICK;
}
struct wt_status_change_data {
int worktree_status;
int index_status;
int stagemask;
int mode_head, mode_index, mode_worktree;
struct object_id oid_head, oid_index;
int rename_status;
int rename_score;
char *rename_source;
unsigned dirty_submodule : 2;
unsigned new_submodule_commits : 1;
};
enum wt_status_format {
STATUS_FORMAT_NONE = 0,
STATUS_FORMAT_LONG,
STATUS_FORMAT_SHORT,
STATUS_FORMAT_PORCELAIN,
STATUS_FORMAT_PORCELAIN_V2,
STATUS_FORMAT_UNSPECIFIED
};
#define SPARSE_CHECKOUT_DISABLED -1
struct wt_status_state {
int merge_in_progress;
int am_in_progress;
int am_empty_patch;
int rebase_in_progress;
int rebase_interactive_in_progress;
int cherry_pick_in_progress;
int bisect_in_progress;
int revert_in_progress;
int detached_at;
int sparse_checkout_percentage; /* SPARSE_CHECKOUT_DISABLED if not sparse */
char *branch;
char *onto;
char *detached_from;
struct object_id detached_oid;
struct object_id revert_head_oid;
struct object_id cherry_pick_head_oid;
};
struct wt_status {
struct repository *repo;
int is_initial;
char *branch;
const char *reference;
struct pathspec pathspec;
int verbose;
int amend;
enum commit_whence whence;
int nowarn;
int use_color;
int no_gettext;
int display_comment_prefix;
int relative_paths;
int submodule_summary;
enum show_ignored_type show_ignored_mode;
enum untracked_status_type show_untracked_files;
const char *ignore_submodule_arg;
char color_palette[WT_STATUS_MAXSLOT][COLOR_MAXLEN];
unsigned colopts;
int null_termination;
int commit_template;
int show_branch;
int show_stash;
int hints;
enum ahead_behind_flags ahead_behind_flags;
int detect_rename;
int rename_score;
int rename_limit;
enum wt_status_format status_format;
struct wt_status_state state;
struct object_id oid_commit; /* when not Initial */
/* These are computed during processing of the individual sections */
int committable;
int workdir_dirty;
const char *index_file;
FILE *fp;
const char *prefix;
struct string_list change;
struct string_list untracked;
struct string_list ignored;
uint32_t untracked_in_ms;
};
size_t wt_status_locate_end(const char *s, size_t len);
void wt_status_append_cut_line(struct strbuf *buf);
void wt_status_add_cut_line(FILE *fp);
void wt_status_prepare(struct repository *r, struct wt_status *s);
void wt_status_print(struct wt_status *s);
void wt_status_collect(struct wt_status *s);
/*
* Frees the buffers allocated by wt_status_collect.
*/
void wt_status_collect_free_buffers(struct wt_status *s);
/*
* Frees the buffers of the wt_status_state.
*/
void wt_status_state_free_buffers(struct wt_status_state *s);
void wt_status_get_state(struct repository *repo,
struct wt_status_state *state,
int get_detached_from);
int wt_status_check_rebase(const struct worktree *wt,
struct wt_status_state *state);
int wt_status_check_bisect(const struct worktree *wt,
struct wt_status_state *state);
__attribute__((format (printf, 3, 4)))
void status_printf_ln(struct wt_status *s, const char *color, const char *fmt, ...);
__attribute__((format (printf, 3, 4)))
void status_printf(struct wt_status *s, const char *color, const char *fmt, ...);
/* The following functions expect that the caller took care of reading the index. */
int has_unstaged_changes(struct repository *repo,
int ignore_submodules);
int has_uncommitted_changes(struct repository *repo,
int ignore_submodules);
int require_clean_work_tree(struct repository *repo,
const char *action,
const char *hint,
int ignore_submodules,
int gently);
#endif /* STATUS_H */
Computing file changes ...
