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Include information on the dangers of passing a user-supplied string as

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a format string.  This will later on be changed to a reference to the
FreeBSD Security Architecture after it has been committed.

PR:		docs/39320
Sposnored by:	DARPA, NAI Labs
This commit is contained in:
Chris Costello 2002-06-13 23:35:22 +00:00
parent a3cce19f7d
commit 7bc7869122
1 changed files with 21 additions and 0 deletions
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21
lib/libc/stdio/printf.3
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@ -700,6 +700,27 @@ a buffer overflow attack.
the FSA the FSA
and and
.Sx EXAMPLES . ) .Sx EXAMPLES . )
.Pp
.\" XXX - rewrite after FSA
The
.Fn printf
and
.Fn vprintf
functions are also easily misused in a manner allowing malicious users
to arbitrarily change a running program's functionality by either
causing the program to print potentially sensitive data
.Dq "left on the stack,"
or causing it to generate a memory fault or bus error
by dereferencing an invalid pointer.
.Pp
Never, under any circumstances pass a string obtained from the network,
a file, or any user as a format string to a
.Fn printf
or
.Fn sprintf
function.
.Xc
.Ec
.Sh SEE ALSO .Sh SEE ALSO
.Xr printf 1 , .Xr printf 1 ,
.Xr scanf 3 , .Xr scanf 3 ,