21334ee1f9
here the details: libio: Ensure output buffer for wchars bug 28828 libio: libio Flush onlu _IO_str_overflow must not return EOF bug 28949 linux: Fix _closefrom_fallback iterates until max int bug 28993
59 lines
2.0 KiB
Diff
59 lines
2.0 KiB
Diff
From 053fe273434056f551ed8f81daf750db9dab5931 Mon Sep 17 00:00:00 2001
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From: Adhemerval Zanella <adhemerval.zanella@linaro.org>
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Date: Wed, 23 Mar 2022 17:40:01 -0300
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Subject: [PATCH] linux: Fix __closefrom_fallback iterates until max int
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(BZ#28993)
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The __closefrom_fallback tries to get a available file descriptor
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if the initial open ("/proc/self/fd/", ...) fails. It assumes the
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failure would be only if procfs is not mount (ENOENT), however if
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the the proc file is not accessible (due some other kernel filtering
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such apparmor) it will iterate over a potentially large file set
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issuing close calls.
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It should only try the close fallback if open returns EMFILE,
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ENFILE, or ENOMEM.
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Checked on x86_64-linux-gnu.
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---
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sysdeps/unix/sysv/linux/closefrom_fallback.c | 11 ++++++-----
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1 file changed, 6 insertions(+), 5 deletions(-)
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diff --git a/sysdeps/unix/sysv/linux/closefrom_fallback.c b/sysdeps/unix/sysv/linux/closefrom_fallback.c
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index 60101aa..a9dd0c4 100644
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--- a/sysdeps/unix/sysv/linux/closefrom_fallback.c
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+++ b/sysdeps/unix/sysv/linux/closefrom_fallback.c
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@@ -30,16 +30,16 @@
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_Bool
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__closefrom_fallback (int from, _Bool dirfd_fallback)
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{
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- bool ret = false;
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-
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int dirfd = __open_nocancel (FD_TO_FILENAME_PREFIX, O_RDONLY | O_DIRECTORY,
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0);
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if (dirfd == -1)
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{
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- /* The closefrom should work even when process can't open new files. */
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- if (errno == ENOENT || !dirfd_fallback)
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- goto err;
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+ /* Return if procfs can not be opened for some reason. */
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+ if ((errno != EMFILE && errno != ENFILE && errno != ENOMEM)
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+ || !dirfd_fallback)
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+ return false;
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+ /* The closefrom should work even when process can't open new files. */
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for (int i = from; i < INT_MAX; i++)
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{
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int r = __close_nocancel (i);
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@@ -54,6 +54,7 @@ __closefrom_fallback (int from, _Bool dirfd_fallback)
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}
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char buffer[1024];
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+ bool ret = false;
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while (true)
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{
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ssize_t ret = __getdents64 (dirfd, buffer, sizeof (buffer));
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--
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1.8.3.1
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