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authorEric W. Biederman <ebiederm@xmission.com>2020-11-21 02:14:36 +0300
committerEric W. Biederman <ebiederm@xmission.com>2020-12-10 21:42:59 +0300
commite06b53c22f31ebba4c46d02fb3a58336135db45c (patch)
tree133bb1ff44d98374290fc7e145f213598fd27811 /fs/file.c
parentd74ba04d919ebe30bf47406819c18c6b50003d92 (diff)
downloadlinux-e06b53c22f31ebba4c46d02fb3a58336135db45c.tar.xz
file: In f_dupfd read RLIMIT_NOFILE once.
Simplify the code, and remove the chance of races by reading RLIMIT_NOFILE only once in f_dupfd. Pass the read value of RLIMIT_NOFILE into alloc_fd which is the other location the rlimit was read in f_dupfd. As f_dupfd is the only caller of alloc_fd this changing alloc_fd is trivially safe. Further this causes alloc_fd to take all of the same arguments as __alloc_fd except for the files_struct argument. Acked-by: Christian Brauner <christian.brauner@ubuntu.com> v1: https://lkml.kernel.org/r/20200817220425.9389-15-ebiederm@xmission.com Link: https://lkml.kernel.org/r/20201120231441.29911-19-ebiederm@xmission.com Signed-off-by: Eric W. Biederman <ebiederm@xmission.com>
Diffstat (limited to 'fs/file.c')
-rw-r--r--fs/file.c9
1 files changed, 5 insertions, 4 deletions
diff --git a/fs/file.c b/fs/file.c
index 0d4ec0fa23b3..07e25f1b9dfd 100644
--- a/fs/file.c
+++ b/fs/file.c
@@ -538,9 +538,9 @@ out:
return error;
}
-static int alloc_fd(unsigned start, unsigned flags)
+static int alloc_fd(unsigned start, unsigned end, unsigned flags)
{
- return __alloc_fd(current->files, start, rlimit(RLIMIT_NOFILE), flags);
+ return __alloc_fd(current->files, start, end, flags);
}
int __get_unused_fd_flags(unsigned flags, unsigned long nofile)
@@ -1175,10 +1175,11 @@ SYSCALL_DEFINE1(dup, unsigned int, fildes)
int f_dupfd(unsigned int from, struct file *file, unsigned flags)
{
+ unsigned long nofile = rlimit(RLIMIT_NOFILE);
int err;
- if (from >= rlimit(RLIMIT_NOFILE))
+ if (from >= nofile)
return -EINVAL;
- err = alloc_fd(from, flags);
+ err = alloc_fd(from, nofile, flags);
if (err >= 0) {
get_file(file);
fd_install(err, file);