[PATCH v2 3/4] merge/pull Check for untrusted good GPG signatures

[PATCH v2 3/4] merge/pull Check for untrusted good GPG signatures

[Sebastian Götte]

When --verify-signatures is specified, abort the merge in case a good
GPG signature from an untrusted key is encountered.

Signed-off-by: Sebastian Götte <jaseg@physik-pool.tu-berlin.de>
---
 builtin/merge.c                    |   2 ++
 commit.c                           |   1 +
 commit.h                           |   4 ++--
 gpg-interface.h                    |   2 +-
 t/lib-gpg/pubring.gpg              | Bin 1164 -> 2359 bytes
 t/lib-gpg/random_seed              | Bin 600 -> 600 bytes
 t/lib-gpg/secring.gpg              | Bin 1237 -> 3734 bytes
 t/lib-gpg/trustdb.gpg              | Bin 1280 -> 1360 bytes
 t/t7612-merge-verify-signatures.sh |   9 +++++++++
 9 files changed, 15 insertions(+), 3 deletions(-)

diff --git a/builtin/merge.c b/builtin/merge.c
index b3788aa..42480e7 100644
--- a/builtin/merge.c
+++ b/builtin/merge.c
@@ -1251,6 +1251,8 @@ int cmd_merge(int argc, const char **argv, const char *prefix)
 					if (verbosity >= 0)
 						printf(_("Commit %s has a good GPG signature by %s\n"), hex, signature.signer);
 					break;
+				case 'U':
+					die(_("Commmit %s has a good GPG signature allegedly by %s, albeit from an untrusted key."), hex, signature.signer);
 				case 'B':
 					die(_("Commmit %s has a bad GPG signature allegedly by %s."), hex, signature.signer);
 				default: /* 'N' */
diff --git a/commit.c b/commit.c
index d0d9135..300cf98 100644
--- a/commit.c
+++ b/commit.c
@@ -1027,6 +1027,7 @@ static struct {
 	char result;
 	const char *check;
 } signature_check[] = {
+	{ 'U', ": WARNING: This key is not certified with a trusted signature!" },
 	{ 'G', ": Good signature from " },
 	{ 'B', ": BAD signature from " },
 };
diff --git a/commit.h b/commit.h
index eada616..2189eb6 100644
--- a/commit.h
+++ b/commit.h
@@ -233,8 +233,8 @@ extern void print_commit_list(struct commit_list *list,
 
 /*
  * Check the signature of the given commit. The result of the check is stored in
- * sig->check_result, 'G' for a good signature, 'B' for a bad signature and 'N'
- * for no signature at all.
+ * sig->check_result, 'G' for a good signature, 'U' for a good signature from an
+ * untrusted signer, 'B' for a bad signature and 'N' for no signature at all.
  * This may allocate memory for sig->gpg_output and sig->signer.
  */
 extern void check_commit_signature(const struct commit* commit, struct signature *sig);
diff --git a/gpg-interface.h b/gpg-interface.h
index c69130f..cbdaf3a 100644
--- a/gpg-interface.h
+++ b/gpg-interface.h
@@ -3,7 +3,7 @@
 
 struct signature {
 	char *gpg_output;
-	char check_result; /* 0 (not checked), N (checked but no further result), G (good) or B (bad) */
+	char check_result; /* 0 (not checked), N (checked but no further result), U (untrusted, good), G (good) or B (bad) */
 	char *signer;
 };
 
diff --git a/t/lib-gpg/pubring.gpg b/t/lib-gpg/pubring.gpg
index 83855fa4e1c6c37afe550c17afa1e7971042ded5..1a3c2d487c2fda9169751a3068fa51e853a1e519 100644
GIT binary patch
delta 1212
zcmV;t1Vj6b3AYlkj0As~0SyFEOqNFh2mr~8{AU1PG9!Ku9w|}@vpZJPg*#s86v-*O
zhafj(DL&&lF<A0)`tvC$E@WHJ2r~0{0ZCh1kHo$b9ih^aD*~)oVvK&yC1(yi)6x_y
zF8V3JpbIY^ZYQ&<Uk#j*ja0`;jw^J+5~!h3qc)ej%g1;Wb0U8cXSuLKdXkx2PUtB4
z>zqQ>O;r+6Qa<VFd?Z<kA#8Ch(&2p+QaoKR;K0{BU;l_DqGU2YCt6Fr4psgB*tPou
z8C@tnj=CqkffSLs=a-5G+h;Y8bkw<s-iIgT{$f^j!)l`hmkz}$nZPxBoPmwU;zIH^
zLN~K=bO>hGBes9{Fcqzh%Wj2h^{ZjI01*KI0kkAVa%poQL}_zlZ*pX5VIVwYX>((5
za%4bdcwudDY-KKPWpqA?0XPH`0RjLb1p-k_mPY~`0|pBT2nPcK1{DYb2?`4Y76JnS
z0v-VZ7k~f?2@qikE`_%uafw)?2m1%-{uDP0Rs1|(F{OVhOSKoH$k!o)x3CO5Z^@El
zxGq=+xQGR&r@3$S<0@SUu@@UuxUH%pD3Q-D`?37Vg*xmo<%+KD)(U~k>XU^b+=70V
zFr?b3DvlFq^B*d%lz=lr!ch6nQbvcwWCD}n2DT3`r?RDkq=7r}qFvEh<dfApA7yR;
z8`OB;$TEKm@jkwG=8vlcKFd>rcM8+9eP66QueaUSz6NhphD3O@E(iX7T@2kxV(dXd
zxG_$z;qqdh<Np6*{J!OD7<b;8M6otxRi0UUN|OngZ4NdYbeU0hneiVEwY2h5xZ4z{
zsXL4>UkGxJ?Pc}MK(e<Q>lV@oumS)Bxd9CXQA~f9M*#=`sXI><#Mh|Ll%uxJqK}<$
zc)VOU|M7H$nU~Bd&(!9WlLk)V)&z>UY~vSc_rVFe1JAY7ThlG1IzE9z6>ly;9W<Ie
zrW&+EU|2KpxZ$0rq-Jn9T{vsi6Qh0j42I3_PLQ5$)qa$}3etj89nJkr^3#KD!xh9*
z4BvmZ0TM||zk);(8@JN=fad9d4hK=Hf1{&&J5DP=<J9wW0IGZ_*p$xvH=WZu8h1r#
z-&1Cjfqp9S1m|b%7<S$7Du_^GfwyFyObC4EMw~6<SwH1<W45gXD*OLAz9x~@tJ8<?
z^Jtn;2$K^0SUY?f@Cu@)V5#TJ_yB~Qw!nY4S8m<?1+xGV0RRDs0Urby0RjLC1p-k_
zmPY~`3;+rV5Mc=}g|{MciR^I*0LA1n{v0`JrvmHmaVfVdlHi8rqLbHhetm3X@&@Ir
zXeh6;re%LlP-QWig+n`!Ae0mFQrnvwOO!ZC8%_&sj-2tVNM{p{WTNusbkj>Mdd`2^
zgn2IBiSf%lm^DyQau7lg)pfK8(7<}-iih0<Mm(k9C_6rNl4sE(`#Aa}K2LGjw*;6_
zqt%Wq<wPe#N15ysVyQhrRmcBJ^&Q!GEW&Mp#@%c+q~S#5UAR4_eeRejBs87Xv&Yt)
zg^u)$-LG%(tX4KA^%L!j<@*Z_A!anKyx}t&F6RX0yYXc)&KtB~l*=nGq9`cf<aD`r
a9*zs=xM)EjeiKg!$s4>o369jT0ssS^s3f2O

delta 7
Ocmdlk)Wf-<hXnu&fC8TY

diff --git a/t/lib-gpg/random_seed b/t/lib-gpg/random_seed
index 8fed1339ed0a744e5663f4a5e6b6ac9bae3d8524..95d249f15fce980f0e8c1a8a18b085b3885708aa 100644
GIT binary patch
literal 600
zcmV-e0;m1ccZd+x>>TST*Lrq1x^ggx^+ymwieO!6X=U~ZH@{avIgxdn#ai{)Ou@Qw
za}Z!boffEq^fn)n?c=IEnDpt59Lnc)aR*;8Z;k>gh_NW;ka;7Mt@v#sG(!Y9SSXWv
zQxd3WlyBr#4ltW6uKOoa6(r3df1VX$cG4`Om6hD-ckaX+Hb_yI?{f`hJQY&k!1cM-
zoGeY~(Z7aYn$W06djh?W|CMs>W=k@jgf=P2D1UA1T%vz0oE|<O<lIacG0xioPtS&U
zNd#}P%YpJr-H65~J^RdqA!YV9BEvh7Gw^CdXg+Hp?kj=KGW|+|&g$4?`trWWGuy$9
zv-|;8Y4(NRHWPyJ{epd{4%FHQKk5j}?0FFDAJ;0kIItZ4y<JS?DIG4~0!#x~;X`!P
zO%+va?@`?yQnhjrP@&#yjY$YO_0yk|1ddhc8V&ru7d%ytet)mF<ZIUbPB3bvhHQ41
zNmnYeFxUMu=m$K5&s=5_F&JSR#oU3Y#X{(q7HTp-VYJ)%JjihbZ@R#GeqmU{>0C4Q
zc}hUG+ighB{7XSaNw_h;=YtqacQ<B(Cg$e)^NTDD-oMD+T`O#-^|-ib>j!<pxHg+(
zlC$%zE836|E*F*((=>O{Nn@K$taZO}!>$t>GMgsw?!=n_#(%X9Ha|$b=H@VstWYe;
zPUQ<L$$#9HTcOLoyEd6*A4TOEe3}c}GiW*^P1Lt{nHYUEAB`Qx7*wizaEyM$?AjVN
mb-6m)4=6PVqdR>h+D!{<c#q1!T9b(}OW7hrrT@nJcBO(OGA4ll

literal 600
zcmV-e0;m1=h9nBV>1C6QsKJEiEJaD@Q3F8s5u<$E+<2(By)JAZSxviTsXg(wKC+O%
zzvV{Z>W3*k?r7~pgmmkbw8-x{Am!eeN)z?cwIHcT2jqgiA(SXo<iO=E?cY80`p#w8
z)O-&?SnwsJ=1VJ-?26&*g88Nr8E=g2onRW^(c+2nJlX)?dmK)tPO0EY-!B!vMCv1)
z-AOW(3WuF+7IdSxMnzrDgnMqVU=|+YFxlY|VeR+Fg<%C@0Xupi0<S7QYJyFTR$}FQ
zzoSAbU>CoCKWKX;!3@L_U=aFUm!M<>ILG}$`bfnadAkLQbI-upV7Qwf^OE&N45Pz<
zk~^KlzNC6)d@QGv=K5-At&A8FS&MQSR`LB}@R1?A3K1p(vM>7CK}EfFhmBJd&cH^-
z(3Ih^`VuoVBB|w~p!Q^#DY%V2A2FhXu<Bp*L)lSCUdqRyI5wxMG&E1sL$)E$Zo&pJ
zgy#;fENqHImgN>LL2!7DhfZ}&;BSAyz=T0#S?2+NET5St@16L?YI?5Io%<uD|2}hl
zx0xsuefz1+bM^-ZIgtKs=)&VAI8(MfytvM>t>%~nsXUb~*EkptHiN?W{=DRu_s;2u
ziHh{2&>;CQO7;>{$DN33_Ef}g+;b<2hIF^p(Y>^riLBb*Y2Xw>F8)jp49&oLKJOic
z+V{Lt!_`eKGhyk5Edie{-^#n!TFlsfux*QBRZEh^4SVePPmb{BvF|>sKd2cYg@vKp
mVI8jcB1(k(tlt^Kr<{EMs>|b*d70nyVMQcc%xEnE(#Uq3d^-35

diff --git a/t/lib-gpg/secring.gpg b/t/lib-gpg/secring.gpg
index d831cd9eb3eee613d3c0e1a71093ae01ea7347e3..82dca8f80bf170fde5705862c3eeb9d994725042 100644
GIT binary patch
delta 2524
zcmV<22_yE^36>qO)dYW)1DFI+OqNFh2mr~8{AU1PG9!Ku9w|}@vpZJPg*#s86v-*O
zhafj(DL&&lF<A0)`tvC$E@WHJ2r~0{0ZCh1kHo$b9ih^aD*~)oVvK&yC1(yi)6x_y
zF8V3JpbIY^ZYQ&<Uk#j*ja0`;jw^J+5~!h3qc)ej%g1;Wb0U8cXSuLKdXkx2PUtB4
z>zqQ>O;r+6Qa<VFd?Z<kA#8Ch(&2p+QaoKR;K0{BU;l_DqGU2YCt6Fr4psgB*tPou
z8C@tnj=CqkffSLs=a-5G+h;Y8bkw<s-iIgT{$f^j!)l`hmkz}$nZPxBoPmwU;zIH^
zLN~K=bO>hGBes9{Fcqzh%Wj2h^{ZjI01*KI0RRX53ySR8{-GbgP@j*nP|DC3r#)Dp
z2P<&T`Q0~>LK@q=ho0q=MufLQlPWFqR35mR(rI(F6VS0oDeH{{JBhX`H?i{4>$Q*u
z&_I~xRn!+usmdp{rtX6{g@{eDP>MBoKG*I*d^QGyiP?Xlz51%C2er?Dt=V~1^&sxy
zetDYbNX(~=kPU(<3T*pC)6mLR)lRiRIK?piia9BQez}5M84jlVCxjJ&H-v~F$|l4w
ziha_;v%#nwK}ABv*)ke2v#@)oM~Wth^P23u1(H;3=$$}!Ax(JiL-t5A6>~P%VM4#0
zG=|5fS<`<4?)8@f$wTkOQ8JR~c0Yv{9#+1ba?u0;%q^?jemepqkdacyZmo)76UH}e
zM%)gY^8)T;PmuQJo!C4xgE?^b0Hp0dHB12&ZNJNKk+=ZKW~dG8$<M>BnuM^iXx$c$
z7{10Z_BDH9{l>#E_hGGBoo)6dWGm^#{HemU0_lGM549PQT%l89fxI0yx5-Kzw$gBQ
z(_vbx%LD-Yvs7ORhmJ40qRG-g0K8w=ATZ%9_0g#931r}y9~c4k>>)_qE$(i{l@Z)?
z-HbCjK>SGAglxQ)Yp|L98R>KeRMK#Jktf@InR{wDPi_K%GRBqLE7}dxUZTDx<>H-P
z_tAfoM5MDA%V+)%*3`(jzZT8wMhEtTabU%Q$C3aG1OU9|f1drO*;1H1hC~98s^<Qh
zJ{8<W8PsJ)aqw94tTzRfL$Rb{3fB#ePvvm_0B2QOZ;g>NsO0i;>=4vk?zi^EuGu~P
z6Y73N>2I%-u?Fv?XciKcv}R|3VxkOXTEBl8Hx)nff5}R%J@8^A^xY;yxt%Fm`7RbB
zMiVEj0529tKC~o7a%poQL}_zlZ*pX5VIVwYX>((5a%4bdcwudDY-KKPWpqA?0XPH`
z0RjLb1p-k_mPY~`0|pBT2nPcK1{DYb2?`4Y76JnS0v-VZ7k~f?2@qikE`_%uafyFe
zqX+v3=l&Eo3sw9)UooXBOSKoH$k!o)x3CO5Z^@ElxGq=+xQGR&r@3$S<0@SUu@@Uu
zxUH%pD3Q-D`?37Vg*xmo<%+KD)(U~k>XU^b+=70VFr?b3DvlFq^B*d%lz=lr!ch6n
zQbvcwWCD}n2DT3`r?RDkq=7r}qFsN{S>%(|Iv-_j02|bJ-^elx@jkwG=8vlcKFd>r
zcM8+9eP66QueaUSz6NhphD3O@E(iX7T@2kxV(dXdxG_$z;qqdh<Np6*{J!OD7<b;8
zM6otxRi0UUN|OngZ4NdYbeU0hneiVEwY2h5xZ4z{sXL4>UkGxJ?Pc}MK(c?g8tWF)
z2(SVG0G$Jv1W`<uM*#=`sXI><#Mh|Ll%uxJqK}<$c)VOU|M7H$nU~Bd&(!9WlLk)V
z)&z>UY~vSc_rVFe1JAY7ThlG1IzE9z6>ly;9W<IerW&+EU|2KpxZ$0rq-Jn9T{vsi
z6Qh0j42I3_PLQ5$)qa$}3etaqQytCyO!Cu%ZNnABQVid>0TM||zk);(8@JN=fad9d
z4hK=Hf1{&&J5DP=<J9wW0IGZ_*p$xvH=WZu8h1r#-&1Cjfqp9S1m|b%7<S$7Du_^G
zfwyFyObC4EMw~6<SwH1<W45gXD*OLAz9x~@tJ8<?^Jtn;2$K^0SUZ1w8So0CreLY(
z%lH6<oVLKXS8m<?1+xGV0RRC22mB4mS|I@6JkDfdjq>@0PopUU*HmnhWEQ1Zn|4r(
z9GSoTgp!+A)nPv6r8B9{T^D^-|BnxB{mbG$(^CGu2K<a9i|8Ws3;As@;!<zuS!$iv
z29IFy#=ssBbfd3{kKcbeAxQSqtg}0L3p+T#HP*}B0Aw|t?fC~{D;t7`)z-+$L&n%Z
z_M36)TxVi(5kG{bkVKh5$EgnbZ8)lo-<8j)H8@#p5FEykPnIF60ER?1=eiWF7zKOi
zdI}!qcpvZT^<N<rtS**b*Uj#8grb70U$O|>8`J7JzzI64FAjfq0ZGU=s`^$G;3P~9
z(R=KHJx6vNd3{)4(><-E1Td4?1OUatS$RONQUKrzEb0;m>?=9CcP<9};$2%xy_?!>
z9-#GIV%_bM#N+3aOII<H(qb9GjdW@m4?!)185PspjMros2;fAlQggqL_@Y;x9pNEO
zq*4B1MHw1?kz{}K*a*MO+LU*2{`fW&d&oGMR0-&l^w)*qzJzCJC)4r4{bk(*0NWBT
zy%rhRpK)3iC=X*4m|BI+EJ$vMX7dhnw(M~x;Rd3_o)?a8Mymw>fcrQlmZBf}#=>gL
z3|==C=V_;x+hN?EQChz2a<mI4)>k6@_qv1p=KLj4k9>c0k87cVv^tWe8;DI7nm}?0
zf>hOGoe5#N567YGQ6Cg$o@X21$j<}&1RU^%Y_NtoAbuSKO2__If2C;^fB2viTOml8
zqZbjENa<ld%X3WIbHu0~*ke8Qp<WWRV(|kDmLLHkGS$Od7{v*2Y_0%_@F585<AGAa
z6C@*Y5=eh}+rL<c(*RW^OzD>69&A7!vDQ@2P~2r@U+LvZ4@Y5V5c&>*yIwtJ^*B_C
z0Urby0RjLC1p-k_mPY~`3;+rV5Mc=}g|{MciR^I*0LA1n{v0`JrvmHmaVfVdlHi8r
zqLbHhetm3X@&@IrXeh6;re%LlP-QWig+n`!Ae4U-@lxBH8%vZpNgGZJY>u4qtVm}Q
zj%1?p=5*6bEqcz{gn2IBiSf%lm^DyQau7lg)pfK8(7<}-iih0<Mm(k9C_6rNl4sE(
z`#Aa}K2LGjw*;6_qt%Wq<wPe#N15ysVyQhrRmcBJ^&Q!GEW&Mp#@%c+q~S#5UAR4_
zeeP74C?qtU)w9ReoQ00`jNPwq@T^ugCiN5Ti{<+Z4IyT&yx}t&F6RX0yYXc)&KtB~
ml*=nGq9`cf<aD`r9*zs=xM)EjeiKg!$s4>o369jT0ssIhKC9;d

delta 7
OcmbOxdzEv;RTcmY+5;N^

diff --git a/t/lib-gpg/trustdb.gpg b/t/lib-gpg/trustdb.gpg
index abace962b8bf84be688a6f27e4ebd0ee7052f210..4879ae9a84650a93a4d15bd6560c5d1b89eb4c2f 100644
GIT binary patch
delta 133
zcmZqRy1*sEm|l?1%*@Ej$i%=9=re5@0|Nu&L_y(=>YJDu6*k{umSl_t3LyXw!<BtX
zhEkV><>GE>E=lCnYu&C?*vSl0pomb%%dj-dsEA)Mq*Svt$mH(j_twWhW_@KtD1fp6
DE~Fa=

delta 52
zcmcb>)xagdm|l?1%*@Ej$iTqhmVVlAqM`Uk^-atZ9rz~(oS3|U#hLd&3{VON0Ad;p
ADF6Tf

diff --git a/t/t7612-merge-verify-signatures.sh b/t/t7612-merge-verify-signatures.sh
index 31b67dd..47a4f80 100755
--- a/t/t7612-merge-verify-signatures.sh
+++ b/t/t7612-merge-verify-signatures.sh
@@ -27,6 +27,10 @@ test_expect_success GPG 'create signed commits' '
 	git hash-object -w -t commit forged >forged.commit &&
 	git checkout initial &&
 
+	git checkout -b side-untrusted &&
+	echo 3 >baz && git add baz &&
+	test_tick && git commit -SB7227189 -m "untrusted on side"
+
 	git checkout master
 '
 
@@ -40,6 +44,11 @@ test_expect_success GPG 'merge commit with bad signature with verification' '
 	grep "has a bad GPG signature" mergeerror
 '
 
+test_expect_success GPG 'merge  commit with untrusted signature with verification' '
+	test_must_fail git merge --ff-only --verify-signatures side-untrusted 2> mergeerror &&
+	grep "from an untrusted key" mergeerror
+'
+
 test_expect_success GPG 'merge signed commit with verification' '
 	git merge -v --ff-only --verify-signatures side-signed > mergeoutput &&
 	grep "has a good GPG signature" mergeoutput
-- 
1.8.1.5