linux kernel patch - suid procs exec'd with bad 0,1,2 fds

From: Zachary Amsden (amsdenzat_private)
Date: Tue Aug 04 1998 - 10:19:01 PDT

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    Patch for current linux kernels
    
    If a priviledged process is exec'd by a user who closes
    file descriptors on it, many poorly written programs do
    not notice and libc printf functions may have access to
    any files opened.  This can be used to crash the system
    by corrupting memory or in some cases, compromise root.
    
    This doesn't attempt to fix the fds for such a process,
    that would be not quite right in a chrooted environment
    with no /dev/null, and creating fake dentries and inode
    is too much work for something that is not quite useful
    
    Instead, we just fall through the standard error checks
    and return EPERM
    
    
    This doesn't break pipelines or any other traditional
    UNIX functionality that I am aware of.
    
    Zachary Amsden
    amsdenat_private
    
    
    
    begin 666 suidbadfd.txt
    M+2TM(&QI;G5X+V9S+V5X96,N8RYO;&0)1G)I($IU;" S,2 Q,3HS-CHT.2 Q
    M.3DX#0HK*RL@;&EN=7@O9G,O97AE8RYC"4UO;B!!=6<@(#,@,3$Z-3 Z,3(@
    M,3DY. T*0$ @+38U-2PQ," K-C4U+#$W($! #0H@"0DO*B!792!C86XG="!S
    M=6ED+65X96-U=&4@:68@=V4G<F4@<VAA<FEN9R!P87)T<R!O9B!T:&4@97AE
    M8W5T86)L92 J+PT*( D)+RH@;W(@:68@=V4G<F4@8F5I;F<@=')A8V5D("AO
    M<B!I9B!S=6ED(&5X96-S(&%R92!N;W0@86QL;W=E9"D@(" @*B\-"B )"2\J
    M("AC=7)R96YT+3YM;2T^8V]U;G0@/B Q(&ES(&]K+"!A<R!W92=L;"!G970@
    M82!N97<@;6T@86YY=V%Y*2 @("HO#0HK"0DO*B!!;'-O(&1O;B=T('-U:60M
    M97AE8R!P<F]C<R!W:71H(&)A9" P+#$L,B!F9',@9F]R('-E8W5R:71Y("U:
    M02 J+PT*( D):68@*$E37TY/4U5)1"AI;F]D92D-"B )"2 @("!\?" H8W5R
    M<F5N="T^9FQA9W,@)B!01E]05%)!0T5$*0T*( D)(" @('Q\("AC=7)R96YT
    M+3YF<RT^8V]U;G0@/B Q*0T*( D)(" @('Q\("AA=&]M:6-?<F5A9"@F8W5R
    M<F5N="T^<VEG+3YC;W5N="D@/B Q*0T**PD)(" @('Q\("%&1%])4U-%5"@P
    M+" F8W5R<F5N="T^9FEL97,M/F]P96Y?9F1S*0T**PD)(" @('Q\("%&1%])
    M4U-%5"@Q+" F8W5R<F5N="T^9FEL97,M/F]P96Y?9F1S*0T**PD)(" @('Q\
    M("%&1%])4U-%5"@R+" F8W5R<F5N="T^9FEL97,M/F]P96Y?9F1S*0T**PD)
    M(" @('Q\($9$7TE34T54*# L("9C=7)R96YT+3YF:6QE<RT^8VQO<V5?;VY?
    M97AE8RD-"BL)"2 @("!\?"!&1%])4U-%5"@Q+" F8W5R<F5N="T^9FEL97,M
    M/F-L;W-E7V]N7V5X96,I#0HK"0D@(" @?'P@1D1?25-3150H,BP@)F-U<G)E
    M;G0M/F9I;&5S+3YC;&]S95]O;E]E>&5C*0T*( D)(" @('Q\("AC=7)R96YT
    M+3YF:6QE<RT^8V]U;G0@/B Q*2D@>PT*(" )"0EI9B H:61?8VAA;F=E("8F
    M("%C87!A8FQE*$-!4%]31515240I*0T*(" )"0D)<F5T=7)N("U%4$5233L-
    !"@``
    `
    end
    



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