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fix uid/gid > 2^31

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This MR revisits a partial fix from 2018. The problem stems from incorrect
handling of unsigned 32-bit uid_ts and gid_ts as signed when values are
large - i.e. when the high bit is set. In that case, pgrep and pkill fail to
identify processes by uid. (They succeed when finding the same processes by
username.) The primary fix for this is to impliment the "FIXME" comment in
proc/readproc.h, the implementation of which allows the removal of the (int)
casts from the partial fix from 2018.

The other fixed code in this MR consists of tests in strict_atol() that
detects and errors out on overflows.

References:
 Merge !146
This commit is contained in:
Todd Lewis 2021-10-25 19:38:10 -04:00 committed by Craig Small
parent 2f293dbf74
commit e500ba6d97
3 changed files with 14 additions and 8 deletions
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1
NEWS
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@ -7,6 +7,7 @@ procps-ng-NEXT
* library: add support for accessing autogroups
* pkill: Check for lt- variants of program name issue #192
* pgrep: Add newline after regex error message merge #91
* pgrep: Fix selection where uid/gid > 2^31 merge !146
* ps: Add OOM and OOMADJ fields issue #198
* ps: Add IO Accounting fields issue #184
* ps: Add PSS and USS fields issue #112

10
pgrep.c
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@ -247,8 +247,12 @@ static int strict_atol (const char *restrict str, long *restrict value)
for ( ; *str; ++str) {
if (! isdigit (*str))
return (0);
return 0;
if (res >= LONG_MAX / 10)
return 0;
res *= 10;
if (res >= LONG_MAX - (*str - '0'))
return 0;
res += *str - '0';
}
*value = sign * res;
@ -323,7 +327,7 @@ static int conv_uid (const char *restrict name, struct el *restrict e)
xwarnx(_("invalid user name: %s"), name);
return 0;
}
e->num = (int) pwd->pw_uid;
e->num = pwd->pw_uid;
return 1;
}
@ -340,7 +344,7 @@ static int conv_gid (const char *restrict name, struct el *restrict e)
xwarnx(_("invalid group name: %s"), name);
return 0;
}
e->num = (int) grp->gr_gid;
e->num = grp->gr_gid;
return 1;
}

11
proc/readproc.h
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@ -152,12 +152,13 @@ typedef struct proc_t {
session, // stat session id
nlwp, // stat,status number of threads, or 0 if no clue
tgid, // (special) thread group ID, the POSIX PID (see also: tid)
tty, // stat full device number of controlling terminal
tty; // stat full device number of controlling terminal
/* FIXME: int uids & gids should be uid_t or gid_t from pwd.h */
euid, egid, // stat(),status effective
ruid, rgid, // status real
suid, sgid, // status saved
fuid, fgid, // status fs (used for file access only)
uid_t euid; gid_t egid; // stat(),status effective
uid_t ruid; gid_t rgid; // status real
uid_t suid; gid_t sgid; // status saved
uid_t fuid; gid_t fgid; // status fs (used for file access only)
int
tpgid, // stat terminal process group id
exit_signal, // stat might not be SIGCHLD
processor; // stat current (or most recent?) CPU