Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 916cafdc authored by Mathias Svensson's avatar Mathias Svensson Committed by James Morris
Browse files

samples/seccomp: fix 64-bit comparison macros 



There were some bugs in the JNE64 and JLT64 comparision macros. This fixes
them, improves comments, and cleans up the file while we are at it.

Reported-by: default avatarStephen Röttger <sroettger@google.com>
Signed-off-by: default avatarMathias Svensson <idolf@google.com>
Signed-off-by: default avatarKees Cook <keescook@chromium.org>
Cc: stable@vger.kernel.org
Signed-off-by: default avatarJames Morris <james.l.morris@oracle.com>
parent a121103c

samples/seccomp/bpf-helper.h

+72 −53
Original line number Diff line number Diff line
@@ -138,7 +138,7 @@ union arg64 { 
#define ARG_32(idx) \

	BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx))



/* Loads hi into A and lo in X */

/* Loads lo into M[0] and hi into M[1] and A */

#define ARG_64(idx) \

	BPF_STMT(BPF_LD+BPF_W+BPF_ABS, LO_ARG(idx)), \

	BPF_STMT(BPF_ST, 0), /* lo -> M[0] */ \
@@ -153,88 +153,107 @@ union arg64 { 
	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (value), 1, 0), \

	jt



/* Checks the lo, then swaps to check the hi. A=lo,X=hi */

#define JA32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (value), 0, 1), \

	jt



#define JGE32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 0, 1), \

	jt



#define JGT32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 0, 1), \

	jt



#define JLE32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 1, 0), \

	jt



#define JLT32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 1, 0), \

	jt



/*

 * All the JXX64 checks assume lo is saved in M[0] and hi is saved in both

 * A and M[1]. This invariant is kept by restoring A if necessary.

 */

#define JEQ64(lo, hi, jt) \

	/* if (hi != arg.hi) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	/* if (lo != arg.lo) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 0, 2), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JNE64(lo, hi, jt) \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 5, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	/* if (hi != arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 3), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo != arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (lo), 2, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */



#define JA32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (value), 0, 1), \

	jt

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JA64(lo, hi, jt) \

	/* if (hi & arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (hi), 3, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo & arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JSET+BPF_K, (lo), 0, 2), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JGE32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 0, 1), \

	jt



#define JLT32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (value), 1, 0), \

	jt



/* Shortcut checking if hi > arg.hi. */

#define JGE64(lo, hi, jt) \

	/* if (hi > arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \

	/* if (hi != arg.hi) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo >= arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (lo), 0, 2), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */



#define JLT64(lo, hi, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (hi), 0, 4), \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JGT32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 0, 1), \

	jt



#define JLE32(value, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (value), 1, 0), \

	jt



/* Check hi > args.hi first, then do the GE checking */

#define JGT64(lo, hi, jt) \

	/* if (hi > arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 4, 0), \

	/* if (hi != arg.hi) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo > arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 0, 2), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JLE64(lo, hi, jt) \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (hi), 6, 0), \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 3), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), /* swap in lo */ \

	/* if (hi < arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (hi), 0, 4), \

	/* if (hi != arg.hi) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo <= arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGT+BPF_K, (lo), 2, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), /* passed: swap hi back in */ \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define JLT64(lo, hi, jt) \

	/* if (hi < arg.hi) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (hi), 0, 4), \

	/* if (hi != arg.hi) goto NOMATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JEQ+BPF_K, (hi), 0, 5), \

	BPF_STMT(BPF_LD+BPF_MEM, 0), \

	/* if (lo < arg.lo) goto MATCH; */ \

	BPF_JUMP(BPF_JMP+BPF_JGE+BPF_K, (lo), 2, 0), \

	BPF_STMT(BPF_LD+BPF_MEM, 1), \

	jt, \

	BPF_STMT(BPF_LD+BPF_MEM, 1) /* failed: swap hi back in */

	BPF_STMT(BPF_LD+BPF_MEM, 1)



#define LOAD_SYSCALL_NR \

	BPF_STMT(BPF_LD+BPF_W+BPF_ABS, \