ericonr
/
util-linux
mirror of https://github.com/ericonr/util-linux.git
1
0
Fork 0
Code Issues Projects Releases Wiki Activity

write: change determination can user write to a terminal 

Earlier test failed when user had write permission, but was not in
special group that owns terminal devices, usually tty.

This made write(1) to fail for root, if the root did not happen to be in
tty group.  In this commit root is granted ot write to anyone, even if
they have mesg(1) turned off.  For an user who is trying to write to own
other session the group write bit is significant only for whether mesg(1)
are enabled.

Signed-off-by: Sami Kerola <kerolasa@iki.fi>
This commit is contained in:
Sami Kerola 2013-08-18 10:44:13 +01:00
parent f7afb6b6b8
commit 0233a8ea18
1 changed files with 5 additions and 4 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

9
term-utils/write.c
View File

@ -73,7 +73,7 @@ static void __attribute__ ((__noreturn__)) done(int);
int term_chk(char *, int *, time_t *, int);
int utmp_chk(char *, char *);
static gid_t myegid;
static gid_t root_access;
static void __attribute__ ((__noreturn__)) usage(FILE * out)
{
@ -120,7 +120,7 @@ int main(int argc, char **argv)
usage(stderr);
}
myegid = getegid();
root_access = !getegid();
/* check that sender has write enabled */
if (isatty(fileno(stdin)))
@ -299,8 +299,9 @@ int term_chk(char *tty, int *msgsokP, time_t * atimeP, int showerror)
return 1;
}
/* group write bit and group ownership */
*msgsokP = (s.st_mode & (S_IWRITE >> 3)) && myegid == s.st_gid;
*msgsokP = !access(path, W_OK);
if (!root_access && *msgsokP)
*msgsokP = s.st_mode & S_IWGRP;
*atimeP = s.st_atime;
return 0;
}