grep malfunctions under heavy load and non-matching lines do not get filtered out

[Sean Lee]

Configuration Information [Automatically generated, do not change]:
Machine: i686
OS: linux-gnu
Compiler: gcc
Compilation CFLAGS:  -DPROGRAM='bash' -DCONF_HOSTTYPE='i686'
-DCONF_OSTYPE='linux-gnu' -DCONF_MACHTYPE='i686-pc-linux-gnu'
-DCONF_VENDOR='pc' -DSHELL -DHAVE_CONFIG_H  -I.  -I. -I./include -I./lib
-D_GNU_SOURCE  -O2 -march=i386 -mcpu=i686
uname output: Linux kate.erexi.com 2.4.18-17.8.0 #1 Tue Oct 8 11:25:39
EDT 2002 i686 i686 i386 GNU/Linux
Machine Type: i686-pc-linux-gnu

Bash Version: 2.05b
Patch Level: 0
Release Status: release

Description:
        Sometimes non-matching lines don't get filtered out by grep.
Sample output of my utility:
{MD4}Uunp5PHNbRq8eKqGbSpVCQ==
{MD5}Gh3JHJBzJcaScd3wyUS8cg==
{RMD160}43qIaB6q/fR6Woa0w5mGk+ezE6s=
{SHA}nU4eI71bcnBGqeO0t9tXvY1u5oQ=
I call grep like this: `./digest $pass | grep SHA` from Perl or bash.
I get about 10 malfunctions on 30K of entries.

Malfunction example:
password: {RMD160}43qIaB6q/fR6Woa0w5mGk+ezE6s=
{SHA}nU4eI71bcnBGqeO0t9tXvY1u5oQ=

        Digest is a qmail utility for generating passwords (MD4, MD4, SHA..)
with each run producing four lines of output.
        It could be the digest utility,maybe sometimes it does not insert
newline.
        At this moment I'm unsure if this is a digest or a bash bug or neither.

Repeat-By:
Generate a random CSV file (30K entries, for example), with two columns,
such as "user,password", then feed it to a script (Perl or bash) to
generate passwords and obtain only the SHA password. 
Sample result of digest: ./digest pass
{MD4}Uunp5PHNbRq8eKqGbSpVCQ==
{MD5}Gh3JHJBzJcaScd3wyUS8cg==
{RMD160}43qIaB6q/fR6Woa0w5mGk+ezE6s=
{SHA}nU4eI71bcnBGqeO0t9tXvY1u5oQ=
Call it like this: `./digest $pass | grep SHA`
Then grep the resulting file for MD4 or MD5 to find problematic lines.
In my case:

Attached is digest I use and the source. For more info, www.qmail.org.

Fix:
        No fixes, I write another script to fix resulting file.

digest.c
Description: Text Data

digest
Description: application/executable-binary