diff options
Diffstat (limited to 'netifd/patches/utils-fix-check_pid_path-to-work-with-delted-file-as.patch')
| -rw-r--r-- | netifd/patches/utils-fix-check_pid_path-to-work-with-delted-file-as.patch | 69 |
1 files changed, 69 insertions, 0 deletions
diff --git a/netifd/patches/utils-fix-check_pid_path-to-work-with-delted-file-as.patch b/netifd/patches/utils-fix-check_pid_path-to-work-with-delted-file-as.patch new file mode 100644 index 0000000..82a6441 --- /dev/null +++ b/netifd/patches/utils-fix-check_pid_path-to-work-with-delted-file-as.patch @@ -0,0 +1,69 @@ +From 8ce3d13d9ba56543c2d627fd429fab171b40994e Mon Sep 17 00:00:00 2001 +From: =?UTF-8?q?Karel=20Ko=C4=8D=C3=AD?= <cynerd@email.cz> +Date: Thu, 28 May 2020 10:43:44 +0200 +Subject: [PATCH] utils: fix check_pid_path to work with delted file as well +MIME-Version: 1.0 +Content-Type: text/plain; charset=UTF-8 +Content-Transfer-Encoding: 8bit + +check_pid_patch is checking if process with given PID and executable +path is running. If this code fails the rest of the code can be +convinced that program is no longer running and possibly spawns new +instance that can collide with already running one. This behavior was +reproduced with hostapd. + +Symbolic link exe in process subdirectory in /proc points to original +executable. The problem is that it reads as original path plus string +' (deleted)' if file is removed. The process is still running but +original file is no longer available on files ystem. + +This behavior is triggered not only when file is removed (unlinked) but +also when file is replaced. This happens clearly on package update. In +general this happens any time all references (hard links) to file are +removed from file system. + +This is not ultimate fix as exe link points to any last reference on +file system with preference for original one. The problem is if there +are multiple references and the original one is removed. This can be +reproduced just by copying executable (hard linking) and unlinking the +original one. In such case exe link would point to copy and not to +original deleted one. + +Signed-off-by: Karel Kočí <cynerd@email.cz> +--- + utils.c | 11 ++++++++--- + 1 file changed, 8 insertions(+), 3 deletions(-) + +diff --git a/utils.c b/utils.c +index ba26952..4f40b4b 100644 +--- a/utils.c ++++ b/utils.c +@@ -176,6 +176,8 @@ crc32_file(FILE *fp) + + bool check_pid_path(int pid, const char *exe) + { ++ const char deleted[] = " (deleted)"; ++ const int deleted_len = strlen(deleted); + int proc_exe_len; + int exe_len = strlen(exe); + +@@ -191,10 +193,13 @@ bool check_pid_path(int pid, const char *exe) + proc_exe_len = readlink(proc_exe, proc_exe_buf, exe_len); + #endif + +- if (proc_exe_len != exe_len) ++ if (proc_exe_len == exe_len) ++ return !memcmp(exe, proc_exe_buf, exe_len); ++ else if (proc_exe_len == exe_len + deleted_len) ++ return !memcmp(exe, proc_exe_buf, exe_len) && ++ !memcmp(exe + exe_len, deleted, deleted_len); ++ else + return false; +- +- return !memcmp(exe, proc_exe_buf, exe_len); + } + + static const char * const uci_validate_name[__BLOBMSG_TYPE_LAST] = { +-- +2.26.2 + |