111 lines
3.4 KiB
Diff
111 lines
3.4 KiB
Diff
From 5e7a3c2e7e118c7f12d5dfda9f9140f638976aa2 Mon Sep 17 00:00:00 2001
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From: Benno Schulenberg <bensberg@telfort.nl>
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Date: Sun, 28 Apr 2024 10:51:52 +0200
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Subject: files: run `chmod` and `chown` on the descriptor, not on the filename
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This closes a window of opportunity where the emergency file could be
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replaced by a malicious symlink.
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The issue was reported by `MartinJM` and `InvisibleMeerkat`.
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Problem existed since version 2.2.0, commit 123110c5, when chmodding
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and chowning of the emergency .save file was added.
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Cherry-picked-by: Lukáš Zaoral <lzaoral@redhat.com>
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Upstream-commit: 5e7a3c2e7e118c7f12d5dfda9f9140f638976aa2
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---
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src/files.c | 18 +++++++++++++++---
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src/nano.c | 12 +-----------
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src/nano.h | 2 +-
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3 files changed, 17 insertions(+), 15 deletions(-)
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diff --git a/src/files.c b/src/files.c
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index 8cdf195..e822068 100644
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--- a/src/files.c
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+++ b/src/files.c
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@@ -1551,7 +1551,7 @@ bool write_file(const char *name, FILE *f_open, bool tmp,
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* set retval and then goto cleanup_and_exit. */
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size_t lineswritten = 0;
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const filestruct *fileptr = openfile->fileage;
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- int fd;
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+ int fd = 0;
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/* The file descriptor we use. */
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mode_t original_umask = 0;
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/* Our umask, from when nano started. */
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@@ -1920,14 +1920,26 @@ bool write_file(const char *name, FILE *f_open, bool tmp,
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goto cleanup_and_exit;
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}
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- if (copy_file(f_source, f, TRUE) != 0) {
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+ if (copy_file(f_source, f, FALSE) != 0) {
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statusline(ALERT, _("Error writing %s: %s"), realname,
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strerror(errno));
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goto cleanup_and_exit;
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}
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unlink(tempname);
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- } else if (fclose(f) != 0) {
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+ }
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+
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+#ifndef NANO_TINY
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+ /* Change permissions and owner of an emergency save file to the values
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+ * of the original file, but ignore any failure as we are in a hurry. */
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+ if (method == EMERGENCY && fd && openfile->current_stat) {
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+ IGNORE_CALL_RESULT(fchmod(fd, openfile->current_stat->st_mode));
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+ IGNORE_CALL_RESULT(fchown(fd, openfile->current_stat->st_uid,
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+ openfile->current_stat->st_gid));
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+ }
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+#endif
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+
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+ if (fclose(f) != 0) {
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statusline(ALERT, _("Error writing %s: %s"), realname,
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strerror(errno));
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goto cleanup_and_exit;
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diff --git a/src/nano.c b/src/nano.c
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index 79b5450..9b9c468 100644
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--- a/src/nano.c
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+++ b/src/nano.c
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@@ -644,7 +644,7 @@ void emergency_save(const char *die_filename, struct stat *die_stat)
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targetname = get_next_filename(die_filename, ".save");
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if (*targetname != '\0')
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- failed = !write_file(targetname, NULL, TRUE, OVERWRITE, FALSE);
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+ failed = !write_file(targetname, NULL, TRUE, EMERGENCY, FALSE);
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if (!failed)
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fprintf(stderr, _("\nBuffer written to %s\n"), targetname);
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@@ -655,16 +655,6 @@ void emergency_save(const char *die_filename, struct stat *die_stat)
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fprintf(stderr, _("\nBuffer not written: %s\n"),
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_("Too many backup files?"));
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-#ifndef NANO_TINY
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- /* Try to chmod/chown the saved file to the values of the original file,
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- * but ignore any failure as we are in a hurry to get out. */
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- if (die_stat) {
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- IGNORE_CALL_RESULT(chmod(targetname, die_stat->st_mode));
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- IGNORE_CALL_RESULT(chown(targetname, die_stat->st_uid,
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- die_stat->st_gid));
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- }
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-#endif
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-
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free(targetname);
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}
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diff --git a/src/nano.h b/src/nano.h
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index 4fd186a..5e22fb7 100644
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--- a/src/nano.h
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+++ b/src/nano.h
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@@ -157,7 +157,7 @@ typedef enum {
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} message_type;
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typedef enum {
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- OVERWRITE, APPEND, PREPEND
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+ OVERWRITE, APPEND, PREPEND, EMERGENCY
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} kind_of_writing_type;
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typedef enum {
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--
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2.45.2
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