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intercept_verify also compares the environment.

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Also mention the overhead involved in checking things.
This commit is contained in:
Todd C. Miller
2022-08-23 11:12:51 -06:00
parent 3d995f7e58
commit 966eae6bf3
2 changed files with 40 additions and 8 deletions
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24
docs/sudoers.man.in
View File

@@ -25,7 +25,7 @@
.nr BA @BAMAN@
.nr LC @LCMAN@
.nr PS @PSMAN@
.TH "SUDOERS" "@mansectform@" "August 11, 2022" "Sudo @PACKAGE_VERSION@" "File Formats Manual"
.TH "SUDOERS" "@mansectform@" "August 23, 2022" "Sudo @PACKAGE_VERSION@" "File Formats Manual"
.nh
.if n .ad l
.SH "NAME"
@@ -3403,19 +3403,35 @@ intercept_verify
If set,
\fBsudo\fR
will attempt to verify that a command run in intercept mode has
the expected path name and command line arguments.
The process is stopped after
the expected path name, command line arguments and environment.
.sp
The process will be stopped after
execve(2)
has completed but before the new command has had a chance to run.
In the case of a path name or argument mismatch, the command will be sent a
To verify the command,
\fBsudo\fR
will read the command's path from
\fI/proc/PID/exe\fR,
the command line arguments and environment from the process's memory,
and compare them against the arguments that were passed to
execve(2).
In the event of a mismatch, the command will be sent a
\fRSIGKILL\fR
signal and terminated.
.sp
This can help prevent a time of check versus time of use issue with
intercept mode where the
execve(2)
arguments could be altered after the
\fBsudoers\fR
policy check.
The checks can only be performed if the
proc(@mansectform@)
file system is available.
The additional overhead from
\fIintercept_verify\fR
can slow down intercept mode considerably for shell scripts that
execute a large number of commands.
This flag has no effect unless the
\fIintercept\fR
flag is enabled or the

24
docs/sudoers.mdoc.in
View File

@@ -25,7 +25,7 @@
.nr BA @BAMAN@
.nr LC @LCMAN@
.nr PS @PSMAN@
.Dd August 11, 2022
.Dd August 23, 2022
.Dt SUDOERS @mansectform@
.Os Sudo @PACKAGE_VERSION@
.Sh NAME
@@ -3224,19 +3224,35 @@ This setting is only supported by version 1.9.8 or higher.
If set,
.Nm sudo
will attempt to verify that a command run in intercept mode has
the expected path name and command line arguments.
The process is stopped after
the expected path name, command line arguments and environment.
.Pp
The process will be stopped after
.Xr execve 2
has completed but before the new command has had a chance to run.
In the case of a path name or argument mismatch, the command will be sent a
To verify the command,
.Nm sudo
will read the command's path from
.Pa /proc/PID/exe ,
the command line arguments and environment from the process's memory,
and compare them against the arguments that were passed to
.Xr execve 2 .
In the event of a mismatch, the command will be sent a
.Dv SIGKILL
signal and terminated.
.Pp
This can help prevent a time of check versus time of use issue with
intercept mode where the
.Xr execve 2
arguments could be altered after the
.Nm
policy check.
The checks can only be performed if the
.Xr proc @mansectform@
file system is available.
The additional overhead from
.Em intercept_verify
can slow down intercept mode considerably for shell scripts that
execute a large number of commands.
This flag has no effect unless the
.Em intercept
flag is enabled or the